There are two very important factors I see....
To be good at design, one must understand production.
I think that even if you can't "code" you need to know what is and is not possible and how code generally functions. Any good designer understands the methods of reproduction whatever they may be - print, web, packaging, fashion, environmental, mechanical, etc. Without knowing what is possible you can not effectively design anything. Sure you may make pretty pictures, but they are worthless if they can't be reproduced for the given medium.
Not everyone who wants to be a designer can be a designer.
Every individual is different with different strengths and weaknesses. It is equally possible for everyone to be successful. Just as it's equally possible for everyone to not be suited for a career in design regardless of the desire. Not everyone who wants to be a designer is cut out to be a designer. Similar to how not everyone who wants to be a professional athlete is skilled enough to be a professional athlete. Desire alone does not make an individual "more skilled" at anything.
I do not wish this to sound overly defeatist or alarming. But really, there is no "one path" to success which can be laid out in front of someone. It's not a math formula to be solved with specific steps that result in a given outcome. It's a fluid, ever changing, landscape which must be adapted to constantly containing many, many, many different routes an individual can pursue.
Truth of the matter is most designers fall onto a spectrum:
Most often you run into those around #2 or #5. More experienced designers will fall in the #3-4 range. And it's all highly dependent upon the actual project at hand. It is rare to meet a designer, any designer, that is at 1 or 6 and is thriving independently.
Larger corporate environments are more apt to hire designers in the 1 and 6 areas for web design. In those environments an entire team is used and what a designer may lack in technical ability is balanced by more technical employees. Both ends of the spectrum are employed so no single person needs to cover everything in most instances.
It is possible to be a successful web designer at #1 or #2. Code building is (rightly) seen as a separate position by many larger or more successful corporations. They want the individuals with an idea a minute and constant ways to replicate the same idea in new, fresh, exciting ways. They seek out those in the 1 and 2 range for design because the technical aspects can always be covered by others.
The difficulty will be in finding employment.
Most small to mid-sized (local or regional) businesses won't see web "design" and web "development" as two completely separate positions. They will expect some overlap. They will want a "web designer" to be able to build that quick email, landing page, or maintain their Wordpress site (web master) without the need to hire a "web developer". That's where things get tricky. It's difficult to move up in the field of "web design" with zero code ability. The market is saturated by new graduates every year. And with the speed at which web building changes, it's a constant learning processes. What was the "norm" just 2 years ago is no longer in use today.
So, if there's zero desire (or ability) to learn the technical aspects of web design, in order to land those juicy corporate positions you'll need to have a portfolio that is breathtaking and exemplary - which she may very well have.
Without any knowledge about the individual it's really difficult to state if they can or can not land those corporate positions which favor creativity over technical ability.
As for "step by step instructions" regarding how to get employed as a web designer. Well, that's nearly impossible to provide without some understanding of the existing skill set.
A general, broad list of what's needed would be similar to:
- Asset creation and photo editing (Photoshop, Illustrator, Sketch, Gimp, whatever) But be aware that their overall use for full page designs has decreased in recent years to a degree. See this 2014 question.
- Basic HTML and CSS. Use of mockup tools, such as Adobe XD, may be helpful here, but a designer worth their paycheck would still understand how basic HTML and CSS function. They aren't "rocket science" or difficult to learn. Not knowing them in the field says more about a designer's desire to be proficient more than anything else. One should at least understand the limitations of the production method.
- For employment, knowing responsive packages may be helpful - Bootstrap, Zurb Foundation, et al. But on your own, some may not be as beneficial as others. See here. Overall the concept of responsiveness and breakpoints can greatly alter layout and design choices, so it should be a concept any web designer grasps. "Mobile first" will shift the design thinking process a great deal.
- Possible exploration into Content Management Systems (CMS) - Wordpress, Drupal, Joomla, Magento, etc. In the case of CMS packages, understanding how they can be templated or "skinned" may be beneficial. There are many small webdev companies out there hiring designers and all the company does is re-template Wordpress or Drupal. So, kind of depends on what type of employment is being sought out. I wouldn't delve too heavily into this, but grasping that these packages can be visually designed for the front end may be helpful.
- Added pluses would be understanding interactivity and what is or is not possible via packages such as jQuery, Prototype, Angular, etc. Knowing you want "that to hide" and "that to slide down and change images" can allow the designer to more thoroughly create an overall design if they grasp what can be done - even if they are completely clueless as to how to write jQuery/Prototype functions.
As a freelancer or independent contractor... to put it rather blunt, there is absolutely no way I know of to be successful without some ability to build at least front-end web pages including understanding CSS, HTML, and responsiveness.
Just as a freelance print designer can not effectively design for print without understanding color breakouts, spot color, registration, pagination, imposition, trim, bleed, overprints.. etc. a freelance web designer, even purely front-end, needs to have the same grasp over similar web-based technical aspects of production.
This question is akin to asking "How can I be an veterinarian who only works on exotic animals? I hate dogs and cats." -- you generally can't. You work up to that achievement, you don't start at that point without some high-end formal education and financial backing to support you until you can establish a reputation which may take years. Are there those employment positions out there? Sure. But landing them is very difficult. More so if there's no proven experience.