My dad is way too touchy-feely with my friends

He never touched me and my sister inappropriately, but he did get a little too close to our friends, always asking my mom to take pictures and using that as an excuse to put his arm around them, grab their hips, putting his hands right below their boobs or just above their butts. My friends complained about it later. He's my dad, he loves us and I don't want him to get in trouble but how do I make him stop... he's worse when he's had a few drinks.