Hotmail sent out spam emails and can’t access the account now

Hi, my son has a problem with his Hotmail account. It has sent out a lot of spam to his friends and he has tried to get into his account to change his password. When he tries this he is immediately redirected to a "account recovery page" that asks for his bank details. He has tried going in from google search page and it is still doing the same thing. On top of that the phone number that is registered with his account no longer exists so he can't even get anything via that route. Can someone help him please? He has applied to University and needs to see if they have got back to him.