I wouldn't say anything to him, unless he brought it up. If you do bring it up, just be prepared for the whole facebook-boundary convo. I don't know your T's stance on that, but if you reveal how you found out then yes, be prepared for a potential unpleasant aspect of the discussion.

As for him being dedicated to your needs. I hope he is aware enough as to practice self-care (e.g. taking time off if need be) so he can be fully present. Also, don't feel guilty or compare who has the bigger problems... That's his job after all. And he knows to take care of himself, so you don't have to (nor shouldn't) take care of him.