i reckon it was cos michael knew his 'step-dad' had abused his brother, or was planning to. chris had obviously been abused as a child, hence his brutal variation n the contract.
eh? when was it revealed that Michael's brother Bug had been abused by that guy?
to me actually, it just looked like the guy got out of prison and was shacked up with the drug fiend mother, but that Michael wanted to be the man of the house and didnt want to let go of the social card cos he knew he'd have no means to feed himself and his brother. Not more. The way the dad gets killed though. *shivers*