Take nothing for granted. That statement of mine that the -ic ending is the -son ending may have been rash. I've had a look at a Serbo-Croat to English dictionary and found the word brcic (brèiæ). It is defined as a diminutive of brk, which means "moustache". So maybe it's a nickname, depending on how it's written in Croat. The word in brackets above should show diacritical marks, but probably doesn't.