>>936759778I mean that sucks what he did, but I'm happy that he didn't go further than that.
How you family reacted also sucks, but don't take it too close to heart, they are reacting according to human instincts and societal norms. Humans afford men and boys more agency because they tend to be physically stronger than women and girls, so usually the threshold for when they consider a man or a boy a victim of sexual assault is a lot higher than it is for women and girls.
This way of thinking, combined with his relatively mild(in their mind) transgression and also likely a wish for their good buddy to not be a bad guy, is why they reacted like that.
If I were you I would talk to your dad one on one about this and let him know that this was a lot worse on you than he might have imagined.
With your brothers there could even be the added issue that he did it to them too, but they let him take it further and coped themselves into thinking that they liked it, making your disclosure of feeling molested conflict with that cope creating cognitive dissonance.