Crazy 2yr old

I don't know what to do with my 2yr old. He bites, scratches, pinches, hits his 4yr old brother all day. Not just his brother though, he also does that to me and dad, and any other kid or adult. The 5yr olds at the playgrounds are scared to be at the playground when he's around because "he's mean". When we're in public idk what to do! If I hit him I'll get judged (not like it works he just smiles and hits back), if I do nothing I'll get judged too! His doctor told me to put him in time out for 2 minutes every time he hurts someone and that's literally a joke. After time out is over he just does it again and again and again. My 4yr old has selective mutism (anxiety disorder) he was always quiet and chill so I've never dealt with a wild kid like his brother before.