Suggest Treatment For Subdural Hematoma, Dizziness And Nausea

Question: My father fell on ice and developed a subdural hematoma that was successfully treated 15+ years ago. He is now 75 very healthy and active (swims every day). He and my mother were just ending a cruise in northern Europe. Early in the cruise he expereiced dizziness and nausea (not something that has happened before and the cruise every year). Ship board doctor was concerned about a heart enzyme out of the normal range so he sent him to a Russian Hospital at a port call. He received a clean XXXXXXX of health and returned to the ship. A week later he had no appetite and was sleeping more than usual. Following a port call they were waiting in line to return to the ship and he fell. Mother said he was swaying before he fell. He was taken by ambulance to a hospital in Norway. CT scan revealed a subdural hematoma. he was airlifted to a regional teaching hospital and surgery was performed. Post Op the Dr. informed my mother that it went well but she would have to wait till morning to see him. I don't know if it was a craniotomy, but I suspect it was performed with bore holes like the last time.
Assuming he recovers well with no infection etc. the Dr. said he could be released from the hospital as early as Monday. If that is the case do you think he would have restrictions regarding transatlantic flight? If so how long would they advise against that? I'm sure he is getting quality care, but we'd still like to get him home as soon as possible without risking aggravating his condition/recovery.