clearly you don't understand his motivation.
he doesn't care about these people. to him, they're beneath him and frankly I can't fault him for having that opinion.
he was an e rank hunter, nobody wanted him and didn't care if he lived or died, so why should he now?
If you're upset about that, then you should also know that he's not the hero of the story, never was, never wanted to be.
he wanted to fix his family and now he's healed his mom, next will be to find his father(once he realizes he's still alive).