I think you are correct that there is more to this story. The local news here in Boston is reporting that the police want to hold him without bail which suggests that the current charges could be upgraded.
Like you, I'll refrain from speculating until the facts come in but I can tell you this from experiences in my own family, a 45-year-old man living at home with his parents is rarely a happy situation.
Family members said the death of Daniel Kerrigan, who rushed to the sobbing Nancy and carried her into a locker room after the 1994 attack on her, was unrelated to the argument with his son early Sunday. Daniel Kerrigan's wife, Brenda Kerrigan, told the Boston Herald newspaper her husband died of a heart attack and there was nothing suspicious about the death.
Mark Kerrigan, who has a history of domestic violence arrests and was sued by his parents to recover money they spent for taking care of his home while he was in jail, was being held on $10,000 bail. He was released from jail in 2007, according to his lawyer, but it wasn't immediately clear why he was serving time or for how long he served.