Hell I live with one. I normally just ignore his behavior when I see he's up to something. I'll usually do what he wants if it's simple and harmless but I make sure to hold him to his word. He sent me to the store to pick up some shaping disks for working on a project. Sure enough even though is costs him gas for me to go there he forgot the Bondo or if he remembered Bondo he'll say he asked for an extra tube of hardener that I forgot. I go for milk he forgets about bread or some stupid shit and he tries to say he told me but I didn't listen. When he starts pulling that shit I'll actually have him dictate a list I write and then pull out the list he watched me make and he's lost for words but will never apologize or say it was his fault ever.