Saying "yeah but your mum is a cripple" to a person who's mum is in a wheelchair isn't funny.

Making "your mum" jokes about the truth is crossing the line imho.

I used the words bullies in quotes for a reason to try to avoid you going into a diatribe about what is a bully - my point was they very compairable to the "bullying" which goes on in balls of fire - something you've already said is wrong