Go to your profile, you can still change your email even though you haven't confirmed one yet. change it to another existing one, or create a new email. Also, make sure your bro has a backup email address, so if he forgets the password, he can get back again.
This is pretty much all we can do. Pm can't "skip a step" or anything of the like, so it's up to you to do something with your email.
NOTE: You can still post on Meta without an email, so you / he can report problems in the future without one, if the problem arises again.