Hmmm, not that I know of. Also, if she cancels Comcast, they will disable the email address so iCloud wouldn't have a way to get it anyway.
It may be possible that you can forward the email from the comcast side. In fact, I know that's possible as I do it. Log onto the account at comcast.net and you can specify the forwarding account. This may stop working once the account is canceled however.