Have you called the city about asbestos? built in the 40s, it may be everywhere. I don't want to get mesothelioma on demo day
Asbestos was used into the 80s in popcorn ceiling texture and linoleum flooring. Joint compound had it into I think the 70s. He has to worry about lead paint since it was built in the 40s. The is a bout a 70% chance that there is lead paint on the walls. With the dogs and his son I would be cautious of the lead paint, but not freak out about it. I would just minimize the amount of dust, plastic the work area, and clean well afterwards.