Pool losing water/center drain leak.

[dsparks81]

Hello everyone,
New to the forum here. I'm looking for opinions on an issue I am having:
We purchased our house last year and it came with an above ground 16x24 pool. From what I have been told by neighbors, the owners before us bought it from some relatives in Florida and had it moved/installed here (Michigan). They installed it with a central floor drain in the center of the pool. The PVC piping of the train comes up near the pump and judging by the valve setup, you can run the suction of the pump from the bottom or the skim. We are losing water and I believe it's that drain line. The piping outside of the pool is super loose, like a union has freed up. The line did split at some point and drained the pool (according to the neighbors).

So I guess the long and short of it is: do I plug the drain? It seems like the most obvious solution.
do i repair the piping? I would love to pump from the bottom, but the weather is so cold here most of the time. I dont want it freezing/splitting every winter.

Any info you guys have would be greatly appreciated!