The registration doesn’t have any sensitive indentity theft type info on it so your friend should be fine there. I just checked my Geico insurance card and it doesn’t have any real sensitive info either. If it had a drivers license number that would be something to worry about.
I’d be more concerned that the person who broke into my car now has my home address. Hopefully there weren’t any house keys in the car?
If all you wanted to know was how to get them replaced please disregard all this and I’ll hop on the hate bandwagon with the others.