Different camper, same plumbing. The female end left on your water line is 1/2 inch. Any 1/2 inch will fit. Here's what I did to replace my end caps so I could drain the low points a bit easier. Reason for the short length of pipe between my female end and the camper male end, was so that extended long thing would fit. It fit inside the actual pipe which allowed me to tighten it down without leaks.
In your case, attach the female end with a cap on it.
If the broken piece is stuck in there, then very carefully drill small holes into it, making a slot so you can get a large flat screw driver on it, then simply unscrew the broken piece out.
The other option might be to cut the end off completely and replace with a shark-bite, then add any type of cap or end you want to it.



