Ask HN: How to get job that encourages mentoring out of college?

A friend is graduating soon and has significant experience developing front-end applications in React. Notwithstanding his great work ethic and command of javascript, he wants to work somewhere that encourages mentorship at work. Some companies have dedicated mentorship programs for all or junior employees. Others seem to leave people to fend for themselves.

What is the best way to find employers that value mentoring? Where have you worked that values mentorship? What would you suggest for finding a mentor, whether on the job or outside of work?