Check out mancrates.com. I gifted a Make Your Own Knife crate and it was a big hit. It gave them an experience of creating something on their own that they actually use on the daily.
They have lots of other crates to choose from too!
Aside from that since I have no experience with people working in the medical field, what about a personalized Yeti or Hydro Flask? I'm sure there is a local boutique near you that monogram. I feel like coffee or tea would be a necessity so this could work well.
I love this Five Year Journal! It's one sentence a day for five years straight. It's such a great record of memories and I think would be great as he enters a new phase in his life! freshchalk.com/joyce_ling#2...
Find out where he will be doing his residency and scope out fun things to do and places to eat in that location. Gift cards to those places with a local guide might be fun. He will be busy during residency so having some ideas of what to do in his free time might be helpful