Instead of hints and positive vibes, what about speaking directly to him?

Tell him you have noticed something amiss. Let him know how much having a therapist can help and how good it feels knowing we have someone to talk about anything and everything and who can help us grow and help us be the person we want to be.

No, we are not our diagnosis. A diagnosis, mostly for insurance purposes, it merely a way to describe how we respond to what we experience.