Has anyone ever delt with someone on drugs?

So I was pretty much at the house most of the day I clean every morning and the house was fine all day. well my mom has been sick so I got out to see her. My fiancé’s co worker took him home. Well he is known for cocaine/crack and his mom to. I got home about an hour after he dropped him off and my house smelt like straight chemicals bad never in my life smelt this before. It was weird though it was in three rooms but nowhere else. He kept saying maybe something died but if it did it would be localized smell. One of the rooms has nothing in it and smelt so bad I was throwing up. I’m just nervous he supposively only smokes weed. This same guy though that took him home always calling him all the time. I just need some things to look out for really. I need advice from people who have seen this. Signs to look for if someone really is using hard drugs. Also I wasn’t saying weed is a drug I’m just saying that’s all he said he has ever done.