Hi Emily,
Welcome to the NeuroTalk Support Groups.

There isn't a forum specifically for brain abscess, but you could try posting in
General Health Conditions and Rare Disorders Forum

I hope your friend makes a speedy recovery.
It's great that he has such caring friends to help.

p.s. One other idea is the
Traumatic Brain Injury and Post Concussion Syndrome Forum
They're a great group and very helpful.
Perhaps the users there might have some support and information for you.

There is a
Caregiver's Support Forum although it's fairly quiet and might not be quite what you're looking for right now.
There are some informational "Useful Sites and Resources" posts in the "stickies" at the top of the forum.