It is not clear in your first message but I am assuming you have checked the "Blocked Senders" in his email account to ensure that he has not blocked the email address or email domain for any of the email addresses that have been sending him emails?
If that is the case there will be nothing further that users of this forum will be able to do/suggest that will fix the issue as it would appear that his email account has been corrupted in some way so I have notified the moderators of the forum about your problem. Once they have read this they may be able to help. They will advise you by posting on this thread.
Meanwhile it will be a waste of your time trying to set up his iPad if his webmail is not working.
