First, I am not a Florida attorney and am not offering any specific advice. Disclaimers aside however, it sounds like your friend may be in a very tough situation. There are a number of things to consider: you state he was in the process of a nasty divorce, was he still living with his wife or were they separated? Is there any reason to believe he is incapable of caring for himself? If so, is it permanent or temporary that he'll need care? Was he represented by an attorney in the divorce? Was she?
If his injuries are permanent and he'll need permanent care, then one possible option would be to initiate a guardianship proceeding and have his daughter be appointed guardian. This may also be available if the disability is temporary, only a temporary guardianship would be available.
If he was represented in the divorce, then his attorney may be able to help a) contact him, and b) secure rulings within the divorce to get him away from his wife.
Another possibility would be to work with your state's Adult Protective Services and have them investigate to see if he is being controlled by his wife against his will. Along those same lines, based on the facts presented a call from the daughter (or perhaps you, given the facts you have presented) may be able to get the local police to do a welfare check on him. Usually, if there is good grounds for concern they will check and will be able to see him and ensure he is safe and not just rely on wife's say so.
Though these are not an exhaustive list of options, they should give you a place to start.
If you have received prior communications via email and think he is at a minimum capable of communicating his desires and needs you could tell the Daughter to contact the local authorities and request them to investigate whether he is being held against his will. It is a crime to hold someone against thier will. If you &/or the daughter have reason to believe his health or welfare is in danger act immediately.