OP I really do sympathise with you, your poor bitten DC! You must be at your wits end.
I think those advocating biting back or saying it worked on them/siblings/DC are coming from a place of "s/he doesn't understand that it hurts". The logic being that once DC understands it DOES hurt, they will stop biting.
But your list of reasons he bites:
- He wants something his brother has.
- He thinks it is funny, like blowing a raspberry.
- I am giving his brother attention.
So 2 out of those 3 triggers are clearly motivated by "malice" (although I'm not comfortable using that word about a 2yr old, but can't think of a more appropriate term.) He knows it hurts - that's (mainly) why he's doing it.
So showing him "this hurts" is not going to have any effect anyway!
I think a PPs suggestion of using toys to model the consequences of biting is really good. Luckily my DC never bit but I'm storing that idea for when he eventually gives me DGC!
From my point of view... I grew up in the early 70s. My younger sister was a biter. When I started school she was 2 and she became very bitey of me. It was a regular thing when I got home from school. She had had my mums attention all day and didn't want to share it! So if I was telling my mum "Today we did our alphabets" she would just lean over and bite me, really quite hard. One day my mum bit her! Yes it did stop the behaviour. BUT just because something has the desired outcome, doesn't mean it was the right thing to do.
I mean you could say "Well it worked" to more or less anything, but it wouldn't make it right. I could say "A woman gave me a shitty look in Tesco so I punched her in the face. She'll think twice next time lol" but I doubt anyone would pat me on the back and say well done!
As an aside, both my parents were physically and emotionally abusive. We were regularly smacked (not a tap on the leg, like a proper thrashing where it hurt to sit down after), given "thick ears" (i.e. smacking someone on the side of their head where their ear is, causing swelling and probably the cause of my lifelong tinnitus, thanks dad) and ocassional punches and kicks. And from talking to my friends at school, that was pretty much the norm for most of them. Perhaps my parents were a bit harsher than most. But I certainly didn't know a single child who wasn't smacked.
As a result we lived in fear. I didn't want my DC to grow up behaving well in sheer terror of the consequences of being naughty. I wanted him to grow up doing the right thing because he knew it was the right thing to do.