my dad has exactly the same issue same fish and all lol...my thoughts for him, and of course I am not someone to take advice from most of the time lol...but I thought he should of course get a smaller clown and maybe keep them in a 10-20 gallon tank with a plexiglass center divider to get them comfortable with seeing each other over the course of however long it may take until you feel that they feel comfortable...
either way I will be watching this thread to see what suggestions come out...good luck