These girls who's photos he was commenting are studying the same thing in university as he does, so he catches up with them at the lectures like 2-3 times a week. Under one girl's photo he wrote: 😳😩😭. Other is: 😘. And the third is 👄👌🏼. I haven't said anything about it to him. Girls, how would you react?
The blowing a kiss one is a little bad, though I think you may be slightly overreacting about the others. Just because a man compliments another woman does not mean that he loves her or is going to leave you. Though there is a fine line between that and pursuing them in a romantic, somewhat creepy way like blowing them kisses.