I had a minor incident on the weekend on a night out in town, similar to your mate i was casually strolling with a ciggie observing the other night owls and such and some lad looking off his head walked right upto me and grabbed hold of my face and kinda pushed my head back, instinct kicked in and i threw a fairly terrible punch and knocked the lad over. A bouncer came over probably expecting me to be about to kick up a fuss but luckily for me he recognised me and had seen that i didn't do much wrong save for standing my ground.
The lad on the other hand was that out of it he physically couldn't stand back up and i was laughing me head off when the police turned up and nicked him for being drunk and dissorderly, they spoke to me briefly as they'd seen the entire incident and after a quick word with the bouncers i was let back in the club to continue my night. Some people are just bad bad bellends mate, hope your neighbour recovers safe and sound.