Have you consulted with a licensed PT? Usually swimming would probably be safe but I know it is the dead of winter in most places now. If you do see a PT ask them about tai-chi a lot of older people do that do improve balance which is important when you do start a exercise routine. There are also chair exercises you can do. Again because of your problems consult a PT before starting.
Oh and something that may help is to make sure you are sleeping on a mattress that gives you the support you need.
Thank you for the advice. I will check into a PT. I will also check out the chair exercises. Again, thank you.