Have you noticed any cognitive changes in your Dad? Do you think his judgment has changed and he is not as safety minded as he was? If this is the case, a doctor can assess him to see if he is still safe to ride his scooter. The doctor might also recommend some safety training and education for your Dad such as a referral to an Occupational Therapist who could work with your Dad to help him learn to be safe on his scooter. If at all possible, help your Dad keep his scooter as long as possible, and work with the doctor or health care professionals together to make that decision.