Their flesh turns to bone, but a new treatment might help them

This is the skeleton of the late Harry Raymond Eastlack Jr, the most recognised case of FOP, which lies in the Mutter Museum of the College of Physicians of Philadelphia. — Wikimedia Commons

What do you do when there are no drugs to treat a crippling disease, especially one that is so rare that there are only approximately one in two million patients worldwide?

You simply have to deal with it the best way you can and hope that someday, there will be drugs to help.