I weep for our future.
Seriously ?
I dunno , Man.
If that was sarcasm , I apologize.
If it was even remotely possible that someone who builds engines for a living would entertain a thought like this for longer than a nano second , I'd be flat ******* amazed.
Especially given that this one has offered to make it right.
And there is a reason why slugs of Mallory metal are usually installed parallel to the crankshaft centerline. I have seen weld built up in balancing holes to add small amounts of weight. But welding cast without pre heating is a gamble ....... pre heating a crank to weld it could be bad for it dimensionally , hence no penetration.
Then , you get a dense whack of mallory metal being spit out as centripetal force increased beyond what is the metallurgical equivalent of a paper clip could hold.
You really want to look for other damage here......Magnaflux the block at a minimum and visually check everything you want to re-use repeatedly.
The crankshaft would not by my friend anymore either , except as a door stop. It took a life cycle worth of beating in a very few seconds.