They can but HealthSouth as you know does not employ their physicians. If you are Medical Director they provide a stipend, usually generous, then it is up to you to bill and collect as a private contractor.
There is good and bad with being a Medial Director (anywhere). The stipends are good but it is not easy work.
It will also depend in large part on the amount of competition you have witin Healthsouth facilities. If there are not many of you admitting there adn there are a lot of beds you will be busy and make money. If there are like 4 other PMR admitting it will get competitive and you may see the negative personality aspects of people.
Finally remember that some people who are pulling in huge salaries at HealthSouth and other private rehab facilities are doing so because they have to round on the weekend frequently. This may be something you do or don't want to do.
Remember also if you choose to do outpt then you'll have to spring for that as well out of your own pocket.