Water problem not repairable?

My 22 yr old Sears Coldspot works great except for a couple of things. I've had the compressor replaced years ago after it burned out.

Recently, after the freezer door was left ajar for 5 days, the unit (both frig and freezer) still worked fine, but water started to collect at the bottom of the frig. Sometimes a little -- 1/4 cup to as much as 3 or 4 cups. I had a repair man come, we cleaned out the tube for the defrost cycle and he tested it somehow. All was fine until the next day and there was a 1/4 cup of water again. I called and he thought maybe a hole had developed internally due to age and that was that.

What's your take? Do I have to breakdown and buy a new frig though this one works well except for the water? Thanks!!