You will both find you are not alone on this subject of sibling help. I don't know what it is, but it seems that one sibling takes on the role of caregiving and the others just back away. Maybe they think, ok, he/she's handling it, seems to be doing ok so I'll stay out of it, or maybe they think good, she's doing it, so I don't have to. Mom lived with me the past year - she has Alzheimer's and my two sisters each saw her 12 hours a month, and called her the morning of the day they picked her up -- that was it. Mom has 7 grandchildren; out of the 7 2 called and not very regularly. Honestly, it bothered me terribly, until I realized that mom didn't care; she never asked, so I got over it. Sure, I would have liked the extra help, but if they don't want to, there's not much we can do about it.
Now one of my sisters has mom living with her - mom's been there for two weeks, since I reached my limit both physically and emotionally and I could no longer take care of mom. I was looking at nursing homes and my one sister just didn't want mom in a NH yet, so she volunteered to take mom. I use to call this sister and just want to vent, knowing she couldnt do anything, but I just needed to feel that someone was there for me, and yet, most times, she was too busy. Now, in the past two weeks, she's called me every day to vent about one thing or another, but I let her talk and vent. I really wanted to not take her calls, but then I thought my mom would end up suffering, because she'd call for some advice, and I don't want mom unhappy. No matter how you slice it, caregiving is a very tough road to travel, and many of us travel it without the help of our siblings, I'm sorry to say,