What is most important is that no matter what he finish law school. I can't stress how important this is if he wants to have a future in medicine. Medical schools frown greatly on pHD, law, etc. graduates that do not finish their program. So, if he can go back and finish, that he would do himself a huge favor. To add to that, a year or two of experience will help.
After that there are multiple routes to take. I strongly advice people without science pre-reqs to consider a post-bac program with a linkage (Scripps, Columbia, Bryn Mawr and Goucher are probably the most known). This would be an efficient way to take the pre-reqs and secure a spot in medical school. The problem with these programs is that they are very unlikely to take someone that started and didn't finish a law/graduate program.
The other option is to start informally taking pre-reqs or apply to other formal programs. The problem with this route is that you don't have much access to advising. Also, as a non-trad you have to have a solid application and show a strong interest in medicine (volunteer, shadowing etc.) and combine it with a good explanation of why you are a non-trad applicant.
That's my two cents.
