My brothers account was recently marked for suspicious activity when he changed his email...

I'm having the same problem with my brother's account, we made an email for the account, but he never used it, and I was the only one with the password. Now he tells me JUST recently to change his email account, wish he would have told me sooner.

But anyways, my guess is that we will have to contact support and have them change the email. This probably happens when the email gets deleted for not being in use for so long.

Hey there, so initially, if I get this correct, he had received a notice about suspicious activity and change his password? How did he receive the notice? I ask because I’m more worried that he went to an unofficial email that looked like it was from Microsoft
and it was actually a phisher that got his password and changed his account

This would be something to bring to MS Support.

https://support.microsoft.com/en-us/contactus

Thank you once again.

The email is not compromised as he has not found any suspicious activity on it and has MFA enabled. In regard to the email change notification, he doesn't see any emails with such information.

It’s says there is suspicious activity on his account. Sorry I don’t have the message in front of me. But literally twice a week he’s having to change his password. When he gets to my house and turns on his Xbox. This is the email I get.