Hi, I think it will be difficult to find. There are a few models that have guest suites (or guest wings) bedroom, bath and sometimes a third room that can be used as a den that can be closed off with a pocket door for privacy. These would be the larger designer or premier homes. That would still leave the problem of a separate entrance and kitchenette, which would cost renovations. Here is a just a thought if your heart is set on the Villages: for the price of a large home plus reno, maybe you could consider 2 smaller side by side villas. That way everyone has their privacy and own space (kitchen, entry, garage, lanai). Everybody happy.
That could work either way, whether an adult child is moving in or a couple moving in elderly parents/in laws. Even in families that get along well, boundaries are very important! Caregiving is one of the most stressful and difficult things in life! 30-40% of caregivers die before the loved one/relative they are caring for due to burnout destroying their own health. If either the parent or the child is toxic, then living together would be a recipe for disaster. There are always other alternatives.
Good luck!