Disclaimer: I don't own Free!WARNING: High Speed Spoilers!
After reading High Speed, I had the impression that Haruka most probably comes from a dysfunctional family, what with his behavior of getting irritated at almost everything so easily. He generally seems like a very lonely person (hence the subtle hints that he gets jealous that Makoto has to take care of other things) who can't be bothered with anything else but swimming and he doesn't like people getting close to him. It's quite tragic, really ;_;
But well, it's merely my opinion (and now headcanon) that Haru doesn't have a great family but it would
make sense as to why Makoto always takes care of him imo
Anyways it'll take some time for me to make the second part of this long comic so please put up with me till then!
P/s: Please don't upload or distribute to other places w/o getting permission!