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

Yes

The word "comemos" has no differences in meaning, grammar, or spelling between Brazilian and European Portuguese. The only difference is in pronunciation. In Brazilian Portuguese, vowels are generally more open and clearly articulated, giving the word a more melodic, syllable-timed rhythm. In European Portuguese, unstressed vowels (such as the "e" in the suffix "-emos") are often reduced or almost silent, making the word sound more "clipped" and stress-timed.

Brazilian Portuguese examples:

1. Nós comemos pizza toda sexta-feira. (We eat pizza every Friday.)
2. Comemos sanduíche no lanche. (We eat a sandwich at snack time.)
3. Nós comemos sorvete no calor. (We eat ice cream in the heat.)
4. Comemos muito no café da manhã. (We eat a lot at breakfast.)
5. Comemos frutas frescas aqui. (We eat fresh fruits here.)

European Portuguese examples:

1. Nós comemos pizza todas as sextas-feiras. (We eat pizza every Friday.)
2. Comemos uma sandes no lanche. (We eat a sandwich at snack time.)
3. Nós comemos gelado no calor. (We eat ice cream in the heat.)
4. Comemos muito no pequeno-almoço. (We eat a lot at breakfast.)
5. Comemos frutas frescas aqui. (We eat fresh fruits here.)