If an old person is unhappy in a place and feels lonely, it can be torture and will likely shorten their life. It is good to get her into her new surroundings as soon as possible, so she can get used to them before she further ages. I would look at the bright side and be happy that there are good genetics in your family, your wife will likely live long as well and can take care of you.
I don't know how long it will take to sell the place, but maybe you can get a short term tenant - for example a family member - in there to take the edge off of it.
Have a beer and relax.
George