A hanger claw is easy to add, though forged dropouts are thicker than stamped ones. If you do this, you may need to use an extra-long rear axle. It will take some trouble, but not too much expense.

Rather than having a hanger welded on, I would recommend having the rear dropouts replaced. While you're replacing the right, you might as well replace the left, so they match. Most bike shops don't do this, but there's one near me who can. Where are you?

Frame builders are not that common, but you can probably find one near you.

Guys, pay attention. His brother died, and our friend wants to rebuild the bike as a connection to his brother. Don't ask him to be rational about it. Just help him do this. For all we know, he's loaded with money.

Is your name really Dave Stohler? That's the name of the main character in Breaking Away, though I think they spelled it Stoller.