I'm 15 and feel like the dud in the family?

My aunt is now on her deathbed and could pass away at any moment and I really want to be beside her when she is ready because she is suffering in agonising pain still hanging on for an unknown reason but I'm getting treated like I'm a 5 year old and get kicked out of many things. When we have family over and we're all sitting in my aunt's room talking to her (by the way she had a massive stroke she cannot respond, but can hear us) there is always something "specific" that is about to be said and I'm told to "leave the room for a second" but my 11 year old sister can stay in there. That really embarrasses me. They treat me like I've not witnessed anything in my life but I've witnessed far more than a 15 year old should. It depresses me and all they do is tell me to go downstairs to my room and play my game (because I play Runescape). I just feel like the dud in the family, all I do is stand there and I feel so depressed because I can't talk to my great aunt who I've only known for 8 months of my life and she is about to pass away. My family does love me but they act like I'm the kid who should cover his ears or cover his eyes when something minor pops up. I've heard the worse swearing all through my life, I've seen so much fighting between my parents (even though they are still together and love each other). I just feel like I'm not allowed and all I do is sit on my game 24/7 now. I'm homeschooled