When a car loses power all of a sudden it usually does not indicate the need for a rebuild. Compression loss due to wear that is extreme enough to require overhaul happens gradually over a very long period of time unless something catastrophic occurs like running without oil or something.

Additionally these engines if properly maintained will go many, many miles without need of overhaul. What is more typical is that a head gasket will blow or maybe will become in need of a valve job. The bottom of the engine does not just wear out overnight. The bottom is very durable.

There are a number of things that could cause a sudden loss of power but it is difficult to troubleshoot all those things over the internet especially with the owner not being the one doing the troubleshooting.

Best of luck,