That's a nice pan even with the repair. I have a skillet with a fancy handle that has a repair like that.
I can't see the color of the weld very well in the photo, but it looks like it would either be copper-zinc (brass), or copper-tin (bronze). I would say you could cook something fatty in it, but avoid acidic food. Whatever the brazing material, the melting point is lower than cast iron. I wouldn't put it under the broiler!