We stick to proper names. Sometimes we say 'caro'. /tizio/ is abosultely out of context, and /fra'/ has a negative meaning and also a meaning related to 'fratello' in the sense of catholicism.

Mas talvez você possa usar também frà.

Where I live we call each other "vecchio/a". It's a really informal word, but it's used a lot by young people.

in Bologna i've heard young people use VEZ - z like pizza- which means kinda'''vecchio mio''.

I think you can say 'FRA' -as fratello- but we use 'Bro' as well; or the proper name or I think you can say your brazilian word and explain the meaning and keep calling your close friends like this! we like languages, we don't want the people to translate everything in italian! Hope it would be helpful! thanks for studying my native language. Ciao Ciao!