I don't think I can help you much since I'm not from that area but at least I can show you how we would write these names in Albanian so it could make it easier to look for him. The last name today would be Muhedin/Muhedini or (probably less likely) Mohedini. His name how we would write it in Albanian would had been either Isuf or Josuf (probably Isuf). His father's name would be written Abdullah. There is a chance his mother's name could be written as Fatime or Fatma besides the version you said. His biggest son name would be written Aqif (Ahmet Korba, we lose the -S which would be there when we would use a greek alphabet to write it. Remember that we were not allowed to teach or learn how to write Albanian so they didn't know how to write their names in Albanian alphabet). Use these names to search in the trees online here. There is a better chance the names are written like this. Also do you have the passanger list of your grandfather? Knowing the village (if he came from one) narrows it down quite a lot. If you have more questions don't hesitate to ask me. Maybe I could help how or where to search for him.