Some of us work full time and some of us live between 1 and one half hours away. They say that we are abandoning him and that they cannot leave him alone at the nursing home. We come as often as we can. Is there any need to have someone there for the 5 to 6 hours they are there and then stay maybe another 2 each day? This is causing so much anger within the family at a time when stress for all is abundant.
You can't abandon your life and responsibilities. I think a three hour round trip drive is a bit much to expect you to do more than a couple times a month in your situation. Given your circumstances, you are doing what you can and should be thanked and not be made to feel guilty. If it is financially possible you might look into hiring someone privately who is local to him a couple times a week to sit with him if that would make your siblings less judgmental and fill in the gaps they seem to feel are yours.
Don't be so hard on yourself. Raising grandkids while holding down a job is quite an accomplishment. Pat yourself on the back for me.
The bigger issue is: are there any unresolved issues in your family?