Topic: Minecraft Split Screen Online

So I have been wanting to play with my brother in the same world. He has an xbox and I'm on Nintendo switch. I was able to get him into my world, but I also want my friend to play with me on my switch. So we tried doing split screen so he could sign in and it says he needs an online account. He got one and it still wont let him sign in. Is it possible to have me and him play on the same switch while also playing with my brother in his xbox at the same time?