Who pays?

I have a rather unusual situation. My client (Mr A) knew an elderly person (Mr X) who needed care in their own home.

Mr A suggested that his brother Mr B could carry out this work and Mr B subsequently started to do this work and continues to do so. It was agreed that £2 500 per month would be paid for this service.

Mr X has given a power of attorney to his son (Mr Y) who deals with Mr X’s affairs and handles his finances etc. For some reason that I am not entirely clear about Mr Y has paid the sum of £2 500 per month from Mr X’s account into Mr A’s account and he in turn has paid amounts over to Mr B.

This has not always been the same regular amount...