Yes, just take him away from his mom and all the other does. You may have to milk the doe a little bit if her udder gets too full. They may cry back and forth to each other for a few days, but they'll be fine.
Scream.....they may scream for a few days! Each of the bucklings I have weaned (I am up to 8 now) has cried, but most have screamed themselves hoarse. Mom is usually ok after a short while though. And all the boys were fine after they recovered their voices. It is hard but cold turkey is the fastest way to go and easiest in mama.
So far I have separated the buckling for almost 2 days and he hasn't cried for her. My bottle screams more for me. Shes getting pretty full though. It was full yesterday and feels tighter today. How much if any should I milk out? Can she get an infection from it?
I don't milk my does that I'm weaning kids off of. To me it just doesn't make sense at it only prolongs their milk production. I've never had a problem with mastitis in any of my does. Now, having said that, I never pull twins or triplets all at the same time, either.
How old is he? If he's already starting to breed now then you need to separate him ASAP. He needs to have a buddy to spend his long ours of SCREAMING with though. Normally they can't breed til 12 weeks old at the earliest. If he's over eight weeks old and he's already started that then you need to separate them. When you start to wean him, they need to be able to see each other. Have them separated between a fence though. Be prepared for screaming! They will lose their voice for a while though. No biggy.