Help replacing LP gas connector
I have a 2009 Fleetwood Highlander popup. I'll save you the long story, but I need to replace a small coupling that connects the pigtail from one of the tanks right where it goes into the Tee and joins with the second tank (this might also be the regulator). After over a dozen stops at local RV dealers, Camping World, gas companies and plumbing companies, no one has been able to tell me the exact name of the coupling or where to find it. I even contacted Fleetwood directly who kindly informed me that they do not provide any support getting replacement parts for their own products. I think this might be called a 1/4" inverted male flare x 3/8" Acme nut, but am not sure. This piece is pretty small (less than an inch long). I've attached a picture showing the broken piece in two parts next to the end of the pigtail it was attached to.
Can anyone tell me what this part is called and ideally where I can get a replacement? Thank you so much in advance.