Engine repair and diagnosis questions.

Hi. First off I'm TJ and I’m new here.
I had a few questions and if anyone has the time to help me out id really appreciate it.
I have aluminum 417 Chevy. It is a bowtie block I believe. I recently sheared a rod. (Broke it near the bottom but did not spin the bearings)
I am having trouble diagnosing what went wrong and I was also wondering if my block is repairable? When the rod got thrown it smacked the block and put two quarter sized holes in either side of the bock. The holes are below the compression (right where the pan bolts on) but there was water in the pan. I believe that it was due only to the fact that the remainder of the top rod. Curled up and cracked the cylinder sleeve.
One question I have is: If I have this block welded and then re-sleeve it will that fully repair my block? I’m not sure about the whole water jacket system. Is it almost impossible to repair an engine that has water in the pan or would a resleeve take care of that?
Another big question was: Why did this rod shear? It is a slightly used engine with only 160 laps on it. We had normal pressures and temps all the way up to the failure, and we had a 7200 rpm chip in the car (which I believe it never even hit.
We warmed the car up and it ran GREAT until the last corner of the last lap. When, with no warning, the rod sheared.
If anyone can help me determine what happened to my engine and if the block is salvageable, I sure would appreciate it.
Thank you for your time,
TJ