No way to know that the kids would not hear that and be traumatized. Did he ask Drew to step outside? Nope. Did he ask him to meet somewhere? Nope. He assaulted him in his mother's home with children upstairs. What if Scout, Danny or Rocco came down stairs for a snack or glass of milk?
I don't get why he didn't press charges. Drew could have said exactly what happened:
I came home and my brother was in the foyer. I spoke and without provocation, he physically attacked me and I defended myself. Drew only thinks Jason knows about the kiss. At the PCPD, Drew could just as easily say he has no idea why Jason attacked him. If Jason decides to tell the reason (he won't) then that's on him.