Replying to Turbo diesel engine problems

so for anyone who has a good knowledge of cars; especially turbo diesels

I drive a 1995 mitsubishi SUV with a 4 valve 2.8 liter turbo diesel. I got the car used and it was not maintained well. I check all the engine fluids and oil level about once a month. I also live in the Caribbean currently where the weather and heat is rough on cars to say the least. 4 days ago I was driving and the engine suddenly sounded horrible. stopped, looked at it, no engine oil leaked out. i did not drive it after that (but maybe it was too late). a guy down the road who builds engines from scratch said he'd fix it. he got it working that day but said due to the engine neglect he wanted to flush it. I took it back to him to flush today and when he flushed it he said he found ground bearings in the engine (damage from running it with no oil). Also the car has a turbo timer and when he turned it on the turbo timer kicked in and the car revved to 6,000 RPM (on a turbo diesel that shouldn't rev about 4,000). the turbo timer malfunctioned and ran for a minute before the guy manually turned it off in the engine bay. Now the head gasket is blown and possibly cracked (thats what the mechanic said at least). My question is, can the engine be saved?