I need a qualified doctor that can properly complete the immigrationform n-648 for my mother.

Your : Your mother's primary care provider should be able to fill out this form. If she does not have one then you will have to find her a primary care provider who is accepting new patients. If she has insurance then you will need to go to your assigned doctor if applicable. If she is a cash patient then you can call and schedule an appointment with a doctor that has openings. The best way to find a good doctor is by word of mouth. Ask friends or family if they have a doctor they could recommend. If not try a local community clinic or look for doctors near your local hospital. Good luck.