I want to be paid as a social media handler for my brother
That sounds like a lot of work. Is there a reason they have decided not to pay you?
The family doesn't trust me with any money anymore.
It sounds like your family may be taking advantage of you. If you didn't offer to give the services for free, they should pay you something. Otherwise, they will have to pay someone else for the services rendered.
I'm trying to handle this for them and my family. If I didn't do this for them, who would have done this for them.
You can bring that up to them when you talk to them. People should be paid for their services, family or not. they would be getting a bargain having you help them then someone outside the family.