The problem with this pen was
"the section hole is too wide for the nib/feed and is also allowing air leakage through the threads with the barrel"
So he had a spare nib unit that I made up a new section, threaded it to take the nib unit. I also made it to take a converter for him. I think that it will only be used as a ED so I sealed the threaded nib unit into the section so that hopefully it will work out as an ED
On the original section there was a small O ring added, but then the section would not sit tight to the body of the pen.
By making a step inside the body I was able to get it so the O ring sets just inside so the section sits tight to the body now.