Coincidence or not?

My little sibling was talking to myself and others on the iphone the other afternoon and I think I might have made her mad.

She was telling myself and others that every evening their 17 year aged child goes to her room, closes the door, and shortly thereafter their gas furnace kicks on.

She said it prefer it was some sort of funny coincidence that the gas furnace kicks on every afternoon after their child goes to her room. I asked if it is the same time every evening and she said that it wasn’t. She said it varies from afternoon to afternoon however that it always happens right away after she goes in her room. The reason she got mad at myself and others is because I said that our nephew must be smoking something that she doesn’t want her parents to think about. She opens her kitchen window, maybe turns on a fan, smokes, then closes everything back up before she goes to sleep. That is why the gas furnace kicks on. I told our sibling to go near her son’s room and see if she feels a draft from under the door if she didn’t think me. She right away got all huffy. She swore up and down that her child was a perfect little angel and that I was making a big deal about a bizarre coincidence with the gas furnace. I raised 3 kids so I think what I am talking about! My oldest was always trying to get away with stuff prefer this. But yes, I observed the draft and I observed that the air conditioning always turned on when she was in her room.
Radiant floor heating