Midpack, I would urge your sister to exercise extreme caution before she upends her life by quitting her job and moving. Sooner or later, your parents will either no longer need help, or they will need help your sister will be unable to provide. More likely sooner rather than later.
My parents are 94 and 93 years old, have always been independent, and are still living in their house. They both expressed to me their desire to remain in their house as long as possible. One difference in my situation is that I live just 10 minutes away. Both of my parents were in great shape until my dad turned 90. Since then, he had a series of mini-strokes resulting in increasing physical and mental deterioration. He has vascular senility and virtually no energy.
I deal with most of the house issues now and there are constantly issues that come up. My dad was very handy and used to do all of this. My mom still does all of the cooking and cleaning. She's a superb cook and I think it gives her purpose. Unfortunately, my dad, who always loved her cooking, eats very little now.
My mom still drives but only in a very small radius to nearby grocery stores and drugstores. Anything further away, I drive her.
6 months ago my dad had a more serious stroke and now he's incontinent and largely immobile, though there's no paralysis. He also no longer has interest in anything and sleeps much of the time, but he's not in pain nor unhappy. Since that stroke, he needs 24/7 home care. My mom doesn't like having someone in the house all the time but she recognizes that the only practical alternative would be a nursing home for my dad. He's getting much better care at home, but it is not cheap. There's a registered nurse during the day for 12 hours, and a nursing assistant for 12 nighttime hours. There have been a few brief occasions (including yesterday) when I had to take care of my dad. I've changed his diaper, shaved him, and moved his mostly dead weight from hospital bed to chair and back. I could not do it on a daily basis. The main daytime nurse is superb and we are very fortunate to have him.
This home health care costs more than $16K/month. My parents have a generous COLA'd pension, though not as generous as your parents' pensions. I have POA and have handled their finances and taxes for several years. Until 6 months ago, money was added to their savings. Now it's flowing the other way. Fortunately, they can afford this expensive home care for several years, if necessary. My biggest concern is if something happens to my mom. In 2013, she was incapacitated twice for about 3 weeks each time, and I had to do much more until she recovered.
It would certainly have been easier for me if they had moved to an apartment or a senior facility. One friend of theirs did that and urged them to join her. They visited her place while my dad was still fairly healthy. Although they liked it, they didn't like it enough to consider moving there.
My task this week is to calculate how much beyond the RMD we can take out of my dad's IRA and still have them not owe any taxes due to their huge medical deductions this year.
I was very fortunate in the parent lottery. We're all trying to do the best we can in the circumstances that exist now.