I have the effect of dad at 45 but I can't do anything else and I don't know how to use the pills, I don't believe it either, the dad never wants to and the brother does xd
The pill doesn't have any use for now. Sorry.
After you reach 45 affection & 50 lust, you can talk to him and there is an option to an ending. Then you could replay the game and go for a low affection run, it has a different "good" ending also.