Is OTHER wrong in the post ? POST : My parents have been divorced for nearly 20 years and are civil. I am very close with both of them. Step mother is not quite so civil. (All are in their mid 60’s) 

My mother is raising my addict, garbage, sibling’s very young child.  She will occasionally ask my father to chip in financially to help with the child and their needs. Dad doesn’t mind helping out here and there, however, SM gets agitated when mom calls and asks for things.  Mom will also sometimes ask for assistance with something related to garbage sibling, and SM would freak the F out if she were to find out.

Dad has asked that I call instead of Mom if the child needs anything (or if there is a garbage sibling situation) and he’ll pass the money or info or paperwork, through me. 

On one hand; I’m an independent adult and have no interest in being the middle man in the continuing bull my garbage sibling  inflicts upon all of us.  I don’t want to get caught up in the drama, and I hate calling dad to ask for money (sometimes a large amount of money) even though it obviously is for the kid. (or paperwork or something for the sibling I have no contact with) I don’t want to share in the responsibility for any of this that has nothing at all to do with me. 

On the other hand, my parents are both being decent people trying to do right by a kid that doesn’t deserve any drama.  They’re asking me to make a few calls (when I talk to them both pretty regularly anyway) to make things run more smoothly. And they are both adults completely capable of deciding when and how to engage or help garbage sibling and that really isn’t my business.

But I really just don’t want to be involved like this. 
(And when I mentioned it to Mom, she snapped at me that it is Dad’s request. When I mentioned it to Dad, he was pretty much ‘for god sakes all of this is hard enough, please just do it.) 

So AITA? 
