What a beautiful idea. That could mean a lot to someone in your son's shoes, and to you as well!
What a puzzle it can be, to figure out how to find mentors, or even positive examples of recovery, when ED's are so rarely talked about openly. Is your son still in high school? If so, perhaps a counselor at his school could help him connect with someone in solid recovery, maybe someone living a happy twenty-something life now? Or if your son's connected to a college, a university counseling center may have a staff member who would be happy to check in with him on this topic.
Also, watch for speaker events in your area, through any ED treatment centers. If you live in the States, you can look up your local chapter of NAMI (National Alliance for Mental Illness). NAMI's speaker events are always free, and the people go through a training process in how to present their own recovery journey in a helpful way. A person willing to share their story of recovery is probably going to be highly encouraging of others who are dealing with the same illness.
This isn't what you asked about, but I'm reminded that I once stumbled on a brief mentor situation for my husband and me. I was searching for family support groups with my D's then-clinic... I e-mailed the director of the clinic my question, and she offered to share contact info. for someone whose D was recovered from ED (for several years). Their family had gone through so much, during a 9 year battle. Now they dedicated some time to support other families through sharing their story and answering questions. My husband and I had breakfast with these total strangers and found that we had many things in common. It was extremely encouraging and helped me not lose hope about better days ahead. Also, they were perfectly lovely people so it helped reinforce that ED's are not a result of bad parenting.
I look upon this forum as my international mentor.
Good luck with your search, and well done with your son's weight going up!!!