His mum banned him from talking to me?

[shutuppauface]

No, there is nothing you can do.
Stop telling him you like him, he can't act on it, and you get him in trouble. Don't kiss him, that's just retarded and serves zero purpose. Sounds like you just want to lead him on to defy his mom because she cut you off and you want to somehow win.

Take it as a lesson to start acting and speaking more like a lady and less like a longshoreman. It's not cute or attractive or impressive, it just makes you look low-class, at best, and trouble, at worst.

PS There's no way to only delete one-half of a conversation on FB, so that's a lie.

EDIT:
There is no way to delete one side of a conversation on Facebook. You can delete entire conversations, but not just what one side said. You've never done it.

And it doesn't matter WHAT you said, she had already told him he could not communicate with you, but you persisted.
Back off and stop bugging him out of some misplaced competition with his mother.
She *will* win, and you don't sound like a very respectful person or friend, anyway.