Can't pick "family"

My aunt never had her own family but ended up befriending a family doctor who also had very minimal family. They became best friends. Well the doc always wanted kids of her own buy focused on her career only for too long and now in her late 40s decided to try to adopt instead. She did adopt. A baby boy. My aunt agreed to help her raise the child. The doc would attend my families functions and was around all the time as if she was family so the family basically took her in that way. My aunt never had much money. She's a massage therapist living alone etc. the doc would pay for lavish vacations for her multiple times a year would buy her expensive gifts etc. in return my aunt basically became her nanny. Doc told her she could be the child's grandma or nonie since she never had her own kids. The doc works two jobs and basically couldn't do it without my aunt who has the kid all the time when the doc is working. In my opinion they can call it what they want but they do use one another. Hey I guess if it works for them who cares. The child however is a nightmare. He's four... Is not potty trained... Has speech issues or I guess under developed speech... He have a lot of behavioral issues. My aunt wants the easy way out of everything. She over coddles the child and will give him anything he wants just to make him stop crying or screaming. When my son is around if the child starts complaining or crying or throwing a huge fit about something my aunt blames my son. My son is 9... And the favoritism is obvious because the little boy is catered to in every way shape and form and my son is being told he is wrong all the time when a large part of it is the child not being able to share or wanting everything himself etc. it drives me nuts. It doesn't matter if someone is a doctor... They are equally capable of doing a horrible job raising a child ... Especially when they've wanted a kid so desperately for so long that they feel bad being too hard on their new child or disciplining them etc and over coddle them constantly. They are both creating a monster. And I now hate attending family functions because everything revolves around catering to this child's sensitivities. And he's the definition of a poorly raised brat. Like they started the dinner an hour and a half late because everyone was making too much noise and he was napping.  Are you serious? So should I just deal with it or what. I guess I don't have an option.