Why are you killing yourself over this? He is your brother, even given the circumstances, and he is a person in need to you and in society, but that doesn't make you the sacrificial lamb here! Even if you happen to be getting paid for your efforts. First of all, one person to take care of all the needs of an ALS patient is nowhere near enough. Second, you have children and your brother has other siblings who, even if they don't have any interest in helping your brother, need to support your decision to help your brother. Walking into a house day in and day out with an ALS person is freakin' hard enough, but to not have any support? That's cruel. And on top of it to deal with ridiculous circumstances with your brother and have your kids and siblings say the things they are with no intention of understanding? Forget that.
I am a co-primary caregiver for my father whose limb onset began about 2 years ago. I have one other person who lives with us and has just as much if not more work than I do. Plus, I have 2 siblings who don't live here and a couple of cousins who also help. The people who don't walk into this house daily don't fully understand the demands but they have no choice but to help. And it's still not enough. No where near! I am relatively young and have so much life to lead but I have virtually no social life and encounter the same feelings that you do...I never want to travel or do any of the things I used too. I go through huge rage regularly and I don't have nearly as good of a reason as you do to want to shut the door.
I am so, so sick right now with a pneumonia type flu but does that mean I can tell my dad that I can't feed him today or go to the bathroom? No way. But who is taking care of me? Yet I have to take care of him and deal with his demands - he is constantly uncomfortable in his body and needs something every second we are around. He has no ability to give us anything yet takes at the highest degree. It's a bad equation for any relationship.
I am always plagued with where to draw the boundaries, but, you know what, there are no boundaries that can be drawn. If they call you at 1, 3, and 5 am to turn them or shift a pillow or pull their legs up - what can I say? Sorry, shop is closed after 11pm? It doesn't work. So where is the middle ground for someone like me or someone like you? You can only demand support from every person you know and TAKE CARE OF YOURSELF. Whatever that might mean to you.
You have a couple options. First to see a therapist to sort out your feelings. Your feelings of guilt and obligation are extreme for someone you don't know and must stem from somewhere. I think whatever you are going to feel, it has to come from a truthful place. Second, to get EVERY single family member involved. You need to be the care manager so to speak and delegate everything out. Doctor's appointments, medication refills, costs, meal prep, and time for relief. Go away for a weekend every few weeks and leave someone else there to deal with stuff. You have too - it's not an option, otherwise you will get sick and you will look back on the time you spent and regret that you didn't utilize options. Third, talk to some people about nursing home care. For a person you truly care about, they say it's the worst thing that could happen...but you can't do it all and DO NOT NEED TOO.
I had to put in my .02 here too. Good luck.