She enjoys it. She’s getting a kick out of making a rule up out of the clear blue sky and seeing the fallout from it, and Alf being upset. She is a first class bully and always will be, with weak little Tommy as her sidekick trying to impress her by joining in.
The way to do it would be to take Alf out for the day, in the woods as it’s so hot, wear him out, show him nature, have a picnic, talk to him, sing to him, really engage. Then let him have half an hour of his favourite show as a reward and a wind-down at the end of a busy day. Screen time shouldn’t be demonised, just used appropriately, but for that you have to actually put the work in as a parent, and sadly these parents are nasty bond idle wastes of space.