Query re whether to be an appointee for my son

Hi - I am unsure whether to be an appointee for my son for his benefits or not. He receives UC and we have just applied for PIP for him. He needs help with post and emails and completing and submitting forms. He also needs support in any assessments. He would be unable to manage his benefits on his own. However he has his own bank account and can access this and manage it on a day to day basis by himself. He does not overspend. I do have LPA for him. Are we OK to continue as we are i.e. helping him on an informal basis with him as the claimant? If it is better to become an appointee then does his benefit have to come into a bank account I set up for him or can it continue to be paid into his bank account? Thinking of the future and the sustainability of it all too. I imagine his sister will have to support him with his benefits in the future. Thanks.