Welcome to OCF, Sai! Im very sorry your grandfather is going thru this! The operation you are talking about is called a mandibulectomy (removal of lower jaw). I have had this surgery. For many it goes smoothly with the doctor using a piece of leg bone to replace the jaw they remove. The hospital stay will be usually be anywhere from one week to one month depending on complications and his recovery. It is a very long surgery, 10+ hours.

Your grandfather needs pain meds. It sounds to me like his cancer is a Stage IV as it is in a large area affecting several things. In my opinion he should have the fentanyl patch at least 50mgs, it will take about 24 hours to work. He may need 75 or 100 to control his pain if it is that bad. But starting at 50 will help and its always easier to move up to higher dosages. This patch needs to have the directions followed exactly with never bending, tearing or folding the patch and no hot baths or showers. It gets changed every 72 hours. He should also have something for breakthru pain. Nobody should have to be in pain. I know how much the jaw can hurt and its terrible. Talk with his doctor immediately and get them to give him something strong for the pain.

I do not know what type of medical professionals or facilities you have available in your country. I would suggest getting your grandfather to the very best comprehensive cancer center where they are the most familiar with head and neck cancers. A small treatment facility may not be experienced in treating someone who has oral cancer, it is often not one of the common ones so the choice of facilities will play a big role in his treatment plan.

Best wishes with everything!