apply for visit visa. You will get a visa for 1 month and extented up to 5 months. When he arrives in doha take him to medical and after getting the medical result go to immigration and make visa for remaining months (as your wish) and ask them for RE-ENTRY (Arabic: AWDHA. They will charge you QR.200. once you get the re entry you can leve the country and come back with in the date of expiry of the visa.