It’s not exhausting at all, although I do hope you all will forgive me for my speed as of late.
That having been said, this is a bit of a tricky situation, yes, but luckily, you’re dealing with a medical pokémon. Medical pokémon are highly intelligent to the point where they possess essentially human levels of awareness only, well, without the ability to speak our language. They have to be, not only to maintain excellent bedside manners but also because they’re often asked to perform complicated tasks that a patient’s life may depend on.
I say all of this because your best course of action is … talking to him. While I wouldn’t recommend being blunt about it (as he is your coworker, and in any case, pokémon are still generally more thin-skinned than humans are), simply informing him that you feel uncomfortable with certain behaviors and outline what you would prefer him to do instead should be enough.
Also, make it clear that you’re not in pain and not in immediate need for medical attention. You can also do this through your actions: as with all pokémon that dote a little too much on trainers recovering from injuries, the more your partner sees you completing tasks on your own, the easier it will be for him to understand you don’t need his help with everything (or anything on a personal level).
Best of luck!