I have a neighbor who's 100 yr old grandmother lives with her. She has an affordable full time care giver that she obtained through the local council on aging. I never would have known a program like this existed...I second Tulip's suggestion to obtain professional input...and Crankin's insight to protect your own independence - particularly with a young child in the house.
You're now part of the sandwich generation in the middle of parenting your young child and your elderly parent.
If you don't grow where you're planted, you'll never BLOOM - Will Rogers