Possibly link him to a video of how you would have done it.Help him how?He could not possibly get a 72" door in a 71" RO.The information he has given is not correct so how can anyone help?
Thanks for your informative reply.Plenty of videos on youtube.I would go to the manufacturers website and watch their installation video. If you have a 72" W door that is the size of the 2 doors together excluding the jamb which is 3/4" each side So 72" + 3/4 X2 for jamb + 1/2" clearance to plumb and shim.I like to put some sort of a rubber membrane at the threshold and up both sides of the RO and don't forget to use a sill pan.You can google it.
If you did get the door in your opening the reason it is not opening and closing properly is that you had no room left to plumb and shim the door so it is out of square.Take a framing square and put it in a corner of the door FRAME and check for square.Set a 4' level on the head and see if it's level.
Time is short today and I have a hard time helping people who can't simply look up the manufacturers installation instructions and videos.No waiting and they are dealing straight with the source.I have never seen any installation instructions for windows or doors that did not explain and spec the RO size.
I thought I did post some helpful advice.It was free and I did not realize I owed you anything for joining the site.My apologies I thought this was a forum for do it yourselfers looking for help and advice. Thanks anyway!