The Salvadoran castaway who was lost at sea for 13 days has extended his hospital stay until at least Monday.

The doctors who have been treating Jose Salvador Alvarenga have stated that he is physically find, but mentally unstable. Psychiatrist Angel Fredi Sermeno stated Thursday that Alvarenga has been dealing with post-traumatic stress and has been afraid on the sea since the incident.

“He doesn’t want to have anything to do with the sea,” Sermeno said. “He wants to avoid being in front of the sea as much as possible.”

According to Yahoo, a medical evaluation will take place on Monday to determine whether or not the once fisherman should remain at the hospital.

CTV News reports that Alvarenga travelled 6,500 miles during his 13 days at sea. He travelled across the Pacific ocean before bad weather sent him into the unknown.

Since being back, Alvarenga has undergone much medical treatment, which is still continuing. His only requests have been to be with his family and to get some tortillas and a pupusa.