You said it was abandoned and apparently has some age to it, does it comply with size and length to be a "rod and pipe" electrode or have any insulating protective coatings on it? If it can qualify put a bonding clamp on it and make it look more justified to be done that way
All I could determine was what you see in the photo. I don't know if this visible pipe is under pressure or not. The highly finished basement rooms completely cover the pipe. The garage, while having the post WWII visible balsam insulation and knot-less plywood, had no pipe stub, or other hints, like a patched over flue location.
Also, the pipe, at about 12 inches below grade, goes straight through old three-core cement blocks and almost certainly the source of the water infiltration. The home owner is bringing in a pipefitter to work towards the removal of the pipe and water sealing the outside of the concrete block basement wall.