Alright, an animal that large would have not let a human survive without burtally harming them, he would have been hospitalize soon as he was found, and wounds from an animal that large would need medical treatments...like stitches. I don't like being a downer on werewolf stories, but I know a flawed story when I hear or see one, which depresses me.
It doesn't help if you call him out on it or not, if he has anger issues to begin with.
Plus, if he is in a medical or healing profession, he should know just by draining the wound is not safe to do on your own. Those wounds of a bear sized dog creatures are not something to just sneeze at.
Working out more,and running will increase over time for anyone who does it often, so that can also been said as normal.
Now, what you need to do is learn how to read peoples energy to know if they are what they say they are, this will allow you to know better on believing them or not. If anything, allow me to do a small reading on him, he must be preasent though, or it is a no go.
Hope everything goes well with that though, in that phase things can get dangerous, because it is usually of the mind.