The human psyche is a weird thing. Maybe you wouldn't feel bad about it, but a lot of people feel horrible for doing things well deserved to terrible people. Many people's brains are just so wired against doing serious harm to others that it messes them up no matter who it was on the receiving end, and emotional trauma isn't the only way this could come back to bite the MC.
True.
But he "has bigger fish to fry".
The potentially ruined life of the terrible assailant of him and his mom is the least of the possible problems he has.
There is the harem.
There is basketball.
There is college.
There is PR (impossible to shield him).
There is Raechel.
There is his personal life.
There is childhood trauma.
There is the "drug lord saga".
...
Plus there are multiple girls he'd like to help.
One of them is McKenzie. Another is the swimmer girl whose name eludes me right now. A third is the corpulent girl.
Ryder could certainly be on the list MC has but he is pretty far down. If at all.
Kind of "pain relieving 101".
If you have a hurting foot and get hit with a hammer onto your head the pain in the foot is forgotten about.
Not saying there is no possible repercussion but it more than very likely is minimal at best.