If you need help in dealing with his mental illness, try going to your town's local MHMR center. Another FABULOUS support group is NAMI...National Alliance for the Mentally Ill. They are everywhere and very helpful.
Hope this helps, and I wish I knew what to do about a computer...maybe contact some large companies in your area to see if they are getting rid of any and would donate one to your family...I've heard that works in some cases!
Blessings to you and yours!