What can we kids do if our dying father is not getting best care possible from his wife?

"Best care possible" is often a subjective judgment. In her late 70s my grandmother was not producing enough red blood cells and fell into a near coma state because her organs were not getting enough oxygen. At her worse, she stopped speaking but would chew and sallow food/water placed in her mouth. With blood transfusions she began to recover. I got the sense that my grandfather would be OK if she declined and died and I was furious with him. I made sure Grandma got regular blood transfusions, often providing the blood myself. She did recover enough to do ADLs again and was again in pain from her back and hip. She would never walk normally again and even walking 30 ft from her bedroom to the kitchen table would be painful for the rest of her life.

A couple of years later my grandfather revealed he had CHF, had been treated for CHF for almost a decade, and his doctor figured he had about a year to live. Grandpa died at 85 with only one worry - that he was leaving his wife of 65 years behind in this world (she was 81). I came to understand that when my grandmother was ill, Grandpa saw her in a painless decline. Knowing he wouldn't be around too much longer because of his own medical issues, he would have been content for her to have a painless exit from this world. He would have looked forward to their heavenly reunion.

Although in my mid 20s I KNEW aggressive treatment with blood transfusions were the "best of care", seeing the painful days my grandmother and my great-aunt (her sister) faced in their last years forced a reevaluation of my grandfather's point of view. I now believe quality of life is more important that quantity of life. Quantity with ill health may be a curse more than a blessing. Grandpa may have very well been right. I wasn't ready to lose Grandma and I wanted to do anything to keep her alive. I wan't really thinking about what was really good for Grandma. Please make sure your are considering what is really best for your dad before you consider confronting your stepmother.

What would you want to do?

Bring in extra services, if he's being cared for at home?
Have him admitted to a different care setting?
Move in with your father and his wife, to support them?

All kinds of things are possible; but without knowing what the situation is at the moment we can't really make any suggestions.

I think we need a little more info in order to offer helpful suggestions. What is his wife able to do now (is she old herself?) and what services if any does she have in place? What help do you and your siblings want to offer that is being rebuffed?