[UncleScratchy]

Sounds like you killed more than just the daedra worshipers in the secret shrine. Those guys are part of a quest but you can kill them with impunity. There are 3 such shrines in the various canalworks of the cantons, each belongs to a different faction/guild quest. You can wait for the quests or just go ahead and kill them if you want and no one will care. I take it you were in the Foreign Quarter waistworks (because that's where you find the killer for the Ordinators). If not, I haven't a clue who you killed. There shouldn't be anyone else down in that canal works besides the shrine worshipers and the killer. So if your son only killed them it shouldn't have been a problem. Perhaps the Ordinators' attacked you for making a false claim about killing the murderer? Doesn't seem likely though as the dialogs don't usually allow stuff like that. If you got kicked out of Hlaalu House as well then your character must have broken one of their house rules (got caught stealing from a Hlaalu vendor, killed a member of Hlaalu house, etc.). The Hlaalu are not associated with the Ordinators and no one cares what you do in the canal work sewers. One reason Ordinators will attack you is if you wear their special armor in their presence. The reward for finding and killing the murderer is your choice of an Ordinator cuirass or an enchanted belt. Perhaps your son did kill the actual murderer (a crazed female dark elf follower of Dagoth Ur), got the cuirass and put in on. That will get the Ordinators on your case forever more (I don't think they ever forget about it either). And perhaps in fighting an Ordinator he accidentially hurt an innocent bystander who belonged to House Hlaalu. Those are my best guesses that might explain what happened. Anyway, you are so completely screwed now that you may be better off restarting the game or going back to an older saved game.