Hi - I'm new here and I really sympathise - this is a frustrating and painful experience - a couple of thoughts......

Butter is probably just feeling a bit threatened and needs to settle down and learn the rules (which doesn't help your poor scratches I know!)

Try hissing at him when he attacks. I had a time when my kitty would attack me to get me out of bed in the morning and I tried a lot of things (a loud clap, shutting her out, saying no, staring at her, etc) and finally, hissing seemed to bring her up short. You could also try making a noise like a wounded cat and then ignoring him - I had quite a bit of success with this too. Another thing I did was to give her lots of interactive play time (fishing pole toys are a hit) - it helped her get out those 'hunting urges'.

Finally - could he be in pain? Has he had a vet check? It's unlikely, but worth considering. Best of luck - I can tell you that my kitty has been wonderful for quite some time now - no violence to speak of - so theres hope.