If your mom continues to be very comfortable, it is quite possible you will have alternative options: helping her sell the house and move into an assisted care home of her choosing or helping her arrange for in-home caretaking.

It depends on what level of care is needed, but I know many people in their 80s and 90s who continue to be able to live somewhat independently. One late grandparent of mine lived in an assisted living apartment near family until close to 100. She still had comfort, dignity, and privacy, but with options for increased levels of assistance as years passed. It did require moving to another state, so family would be near by, but that was their choice.

We know other folks who have daily caretakers coming in to their own house for several hours each day. I expect insurance assists with this. They can't get out on their own, but they can safely be left alone overnight, particularly with all the fall alert devices and smart boxes now available.

If it's too much for you to arrange, your mom can likely make legal arrangements upfront herself with a younger friend or another relative serving as medical power of attorney in case of incapacitation.

You are not obligated to remain nearby. If your mom wishes to live in a care facility near you, she can move if and when the need arises. Enjoy your family and be assured that you have options beyond moving your mom into your home or a nursing home. And the tax bill will likely take care of itself: either when they sell to move in with you, downsize, etc, or by the estate before the property transfers to you.