HelpAls, there are several things you can do. To get more helpful responses, I'd suggest that you post a new thread with that title in this part of the forum--just your own thread, so more people see it--as this persons main question has been answered, it's possible no one will see yours.
The ALS center you see should have an occupational therapy dept--if they do, they can also discuss options to help with dressing and the like. Unfortunately, when the arms go completely, more help is needed from the caregiver. Button down shirts are easier when the arms can't be lifted, for instance, for a caregiver to put on. Pants that don't have zippers...that kind of thing.
There are computers that work with the eyes, and with voice. If he can't grip a gripper to open it, then one wouldn't likely help. I think you['ll have to look more at ways to do things he does now adapted to be done without much arm/hand use.
I've only got one arm about all useless now, but I've found that I do better with no zippers, slip in shoes, I can lift my arm, so I don't need button shirts (I can't button them anyway) but for a man who can't raise his arms, they are going to be easiest to put on.
You can also contact the ALS assoc. in your area for tips and suggestions as well.