1995 Chevy Suburban messed up engine

Engine Mechanical problem
1995 Chevy Suburban V8 Automatic 90,000 miles

About two months ago, I noticed the the oil pressure gauge was reading 0 - 10. I checked the oil, it was fine. I preceded to drive it another 20 miles or so and the engine started to "hiccup" or hesitate but died. I took the vehicle to a mechanic. He ran some diagnostic checks and did an oil change and the guage was working again. The next day we were taking my daughter to the airport approximately 65 miles from where we live. Vehicle ran great for the first 25 miles and then the oil pressure read 0 and the vehicle lost its get up and go and seemed like it took forever for it to shift to a higher or lower gear but never stopped running. We took it back to our mechanic and he is now telling us the engine is shot. Is it or should we be looking for some other source of failure? Thanks for your help.