Why is my guy friend always so worried about me?

I have a friend who is a guy who is always checking on me and asking me how I'm doing. Yesterday a stranger was starting to get combative, so I called him for backup. He came sprinting and apologized for not being sooner. He even put himself between me and the combative customer and after it was resolved, he said he would "wind sprint it" next time. He knows I have low blood sugar so he always checks to make sure that I get my lunch. And he's convincing me to take a huge risk by going back to a school that is fast paced so I can get a promotion. I don't know if he acts like this our mutual friends who are girls but he has said he likes to check on everyone.
Why is my guy friend always so worried about me?
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