There's nothing wrong with beatings, as long everything is explicitly consensual (my ex used to complain I didn't enjoy beating her enough
).
Anyway, this guy sounds like a twat, abandon him as a friend or intervene by beating him up or whatever.
I don't really understand threads which basically start "My friend is really shit...". If anyone I knew seriously started being shit (and I'm not talking about unreliable, or a bit moody after a relationship breakup, but genuinely a poor example of a human being) I simply wouldn't associate with them anymore. Why would you?