Hope all is going well in the DEN household this morning/afternoon. Here's my tuppenceworth....he's 21, an adult and he had permission from Mr Den so in his eyes there's no problem. You on the other hand do have an issue with it and are perfectly entitled to feel that way. I reckon that a proper, calm, sit down family meeting is needed. You ALL live in the house so what goes on in it affects you ALL therefore you ALL need to be on the same page where house rules are concerned and don't let Mr Den leave it all up to you :)
*LMAO @ boxy "What if there were to be a fire?" I totally get what you're saying boxy but it didn't have make me LOL.