Attendance allowance is not means tested. If your father is active he will not be able to claim it. However, I would have thought the fact that he has a pacemaker would have restricted him to a certain extent. I wouldn't have thought he could walk very far. You should get the forms and fill them in to make sure. There is no harm done by applying and he might be missing out. I think you can get the forms from the local office of social services. When you complete the forms you should remember that the questions about movements such as how far can you walk mean without pain. You do not have to be a helpless invalid to claim it.