If the parking spot is properly designated, probably there's no point in fighting the ticket.  Most jurisdictions will only issue the ticket, only convict for the violation, when the space is marked very clearly both on the pavement and with a sign on a pole or wall at the curb end of the parking space.  If the space was properly marked, the "I forgot" defense doesn't really work because the man still wasn't driving or parking with his eyes shut.  If there was no above-the-pavement sign, though, he might be able to beat the ticket on that basis.