Is the word deles the same in Brazilian and European Portuguese?

Yes

The word "deles" is identical in spelling, meaning, and grammatical function in both Brazilian and Continental Portuguese. It is a contraction of the preposition de (of) and the pronoun eles (them). The only difference is in pronunciation. In Brazilian Portuguese, the vowels are generally more open and clearly articulated. In Continental Portuguese, unstressed vowels undergo significant reduction; the "e" sounds often become neutralized or nearly silent, making the word sound much more clipped (closer to "d'lès").

Brazilian Portuguese

1. O carro deles é muito legal. (Their car is very cool.)
2. Eu vi os amigos deles no shopping. (I saw their friends at the mall.)
3. O problema deles é a falta de tempo. (Their problem is the lack of time.)
4. O trem deles está atrasado. (Their train is late.)
5. Eles gostam do jeito deles de agir. (They like their way of acting.)

Continental Portuguese

1. O carro deles é muito fixe. (Their car is very cool.)
2. Eu vi os amigos deles no centro. (I saw their friends in the city center.)
3. O problema deles é a falta de tempo. (Their problem is the lack of time.)
4. O comboio deles está atrasado. (Their train is late.)
5. Eles gostam do modo deles de agir. (They like their way of acting.)