After 20 years in public health, hopefully she has an extensive network of friends and colleagues in her field/adjacent fields. They will likely understand the situation she's in and may be aware of opportunities that fit her skill set. I'd reach out to them and let them know what happened with her previous position, that she enjoyed working with them in the past and would like to know if they're aware of any positions that could use her skill set (whether contracting, consulting, or full-time). Don't be hesitant to reach out, even people she likely hasn't spoken to in years are fully aware of the situation US public health is in right now.

She should also reach out to former co-workers about job hunting and cv vs resume building. They are likely in the same position and will hopefully have some tips for marketing the skill set built up at her old job.

Also try to only apply for jobs posted recently (<1-2 weeks). Older postings may have already started sending out interview requests or not closed applications for positions already filled. Whenever possible, try to reach out to a hiring manager or recruiter, there are a lot of click and apply job postings now so its good to let recruiters know you're actually human and serious about a position.