Marie
Your father will be assessed with the Cochlear Implant, so to a considerable extent it will depend on the level of hearing he now has. Also, his hearing problems will have limited impact on his ability to complete the other Daily Living activities, so does he have other problems that will help him to score points?
I would start by having a look at our PIP Claim guide for the criteria that he will need to meet
www.benefitsandwork.co.uk/help-for-claimants/pip You should also have a look at the websites for the various deaf charities, they may have PIP information especially for deaf people.
Gordon