Problems with xbox profile turning on/log in by itself on different consoles?

On your brothers Xbox, go to Settings > Account
> Sign-in, security & passkey

1. Select Instant sign-in. Make sure it's not your profile.
   
2. Then Change my sign-in & security preferences
   
3. Select Customize (all the way to right)
4. Set Delay automatic sign-in to Ask before signing in and/or set
   Ask for my passkey to sign-in to Passkey required.

step 1 should say "Select Instant sign-in. Make sure it's on your profile" as it is your profile that is signing in automatically on your brother's Xbox.

if you want to allow your brother to play games purchased on your account without you being signed in then you could make his Xbox your Home Xbox (he could also make your Xbox his Home Xbox so that you can play his games). the following link has all
the information you need, but if you have any further questions we're here to help

https://beta.support.xbox.com/help/hardware-network/console/my-home-xbox

On your brothers Xbox, go to Settings > Account
> Sign-in, security & passkey

1. Select Instant sign-in. Make sure it's not your profile.
   
2. Then Change my sign-in & security preferences
   
3. Select Customize (all the way to right)
4. Set Delay automatic sign-in to Ask before signing in and/or set
   Ask for my passkey to sign-in to Passkey required.

Hi and thanks for reaching out. I hope you’re doing well. I'm an Independent Advisor and a Microsoft user like you and I'll be happy to help you.

There could be several reasons why your Xbox One is turning on by itself. Here are a few things you can try to troubleshoot the issue:

1. Check the power settings: Make sure the power settings on your Xbox One are set to "Energy-saving mode" instead of "Instant-on." The instant-on mode can sometimes cause the console to turn on by itself.

2. Check the controller: Your controller may be turning on the Xbox One by itself. Try removing the batteries from the controller and see if the console still turns on by itself. If it doesn't, then the controller may be the issue.

3. Check the power cord: Make sure that the power cord is properly connected to the console and the wall outlet. If the cord is loose, the console may turn on by itself.

4. Try a different power outlet: The issue could be with the power outlet that the Xbox One is connected to. Try connecting the console to a different outlet and see if the problem persists.

I had this problem before but I got it working after a while. Try turning off your console and turning it back on. Then, press the 2 sync buttons, one is on the controller and one is on the console itself, at the same time. If that don't work, turn off the
console again and turn it back on and try to press each sync button in a different combination. Hope this fixes your controller problem.

Maybe a power surge coming from the wall socket? I had a tv and HD sat receiver that would come on for no reason, when ever it felt like. After a house blessing and an electronic exorcism (lol), I unpluged the unit and moved it to a different room, problem
solved. Check the socket and surge protector.