Sounds like Jack needs some testing and serious vetting.
Has he been checked for bladder stones? What testing has been done?
You mention money is a huge issue. If you cannot afford to care for him, please make some sort of decision for him. It sounds like he is suffering. Just so heartbreaking to read this.
There are rescues who would take him and try to help him. I just hope that he has not been left untreated for too long.
