I think it's totally doable and the options others have given are wonderful. We are in TV with the parents and it works very well, us in a house and them in a villa. You may want to consider buying close to healthcare and shopping so they'll be able to drive a golf cart to those places on their own if they still can. Less running around for you and independence for them. Best wishes!

The Lantana has the best floor plan. The front entrance would be used for in-laws. Leading to 2 rooms and bath. A door can be installed in the foyer lleading to main house. Rear bedroom window can be converted to slider for private outdoor space.

I have seen this and it works well.