Bit of an odd one.
Long story short, split up with ex and DS is living with his mum.
DS has a Nintendo Switch, and we used to have a family account shared with his cousins, controlled by my ex's brother-in-law that I paid half for. We used to play Minecraft etc together but my ex didn't really get involved. It was a 'dad thing'.
Her brother-in-law has now taken it upon himself to remove all my parental controls, setup DS with a new login controlled by him, all behind my back or with consent and is refusing to give me the username so I can keep playing online with DS, as he has 'sided' with my ex. DS is now upset as he cant play with me and my ex hasn't done anything about it, not even get herself setup with parental controls!
AIBU in thinking that it is very spiteful to do this and very irresponsible as now neither I nor my ex have any visibility over DS' online activity?!