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

No

While the meaning, spelling, and grammatical gender of "filha" are identical in both dialects, there is a difference in typical usage regarding the definite article. In Brazilian Portuguese, it is standard to omit the definite article before possessive pronouns (e.g., minha filha), whereas in Continental Portuguese, the article is almost always included (e.g., a minha filha). Additionally, pronunciation differs significantly; Brazilian Portuguese features more open, melodic vowels, while Continental Portuguese uses "reduced" or closed vowels, which often makes the final "a" in "filha" sound much more subtle or even nearly silent.

Brazilian Portuguese

1. Minha filha está dormindo. (My daughter is sleeping.)
2. Eu amo minha filha. (I love my daughter.)
3. Minha filha vai para a escola. (My daughter is going to school.)
4. Minha filha é muito inteligente. (My daughter is very intelligent.)
5. Onde está minha filha? (Where is my daughter?)

European Portuguese

1. A minha filha está a dormir. (My daughter is sleeping.)
2. Eu amo a minha filha. (I love my daughter.)
3. A minha filha vai para a escola. (My daughter is going to school.)
4. A minha filha é muito inteligente. (My daughter is very intelligent.)
5. Onde está a minha filha? (Where is my daughter?)