Thanks for the link to FamilySearch. That was a great find, and apparently there was a fourth son that I did not know existed.
I took Kuscha from Forseck's 1910 border crossing. I'd seen the 1914 record, but never thought to flip to the next page. Thanks for that too!
Chances are Kuscha and Kaskow are the same place. In any event, I can't find either one of them! I'm wondering if the borders of Austria were different than what we see today, and perhaps he's referring to a place within the Austo-Hungarian Empire.