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

No

While the spelling and the fundamental meaning of "irmão" are identical in both variants, there are differences in grammar, pronunciation, and typical usage:

• Grammar: In Continental Portuguese, it is standard to use a definite article before possessive adjectives (e.g., "o meu irmão"). In Brazilian Portuguese, this article is frequently omitted ("meu irmão").
• Pronunciation: In Brazil, the nasal diphthong "ão" is typically more open and resonant, and the "r" is often a light tap. In Portugal, the vowels are more compressed or "closed" due to the stress-timed nature of the dialect, and the "r" can vary from a flap to a more prominent uvular sound.
• Typical Usage: In many Brazilian dialects, "irmão" is a very common slang term used to address friends (similar to "bro"). In Portugal, while "irmão" is used for biological siblings, the slang "mano" is much more characteristic for addressing friends.

Brazilian Portuguese Examples

1. Meu irmão é muito legal. (My brother is very cool.)
2. Fala, irmão! Beleza? (Hey, bro! You good?)
3. Eu tenho um irmão mais novo. (I have a younger brother.)
4. Ele é como um irmão para mim. (He is like a brother to me.)
5. Vou viajar com meu irmão. (I am going traveling with my brother.)

Portuguese (Portugal) Examples

1. O meu irmão é muito fixe. (My brother is very cool.)
2. Olá, irmão, tudo bem? (Hello, brother, is everything well?)
3. Eu tenho um irmão mais novo. (I have a younger brother.)
4. Ele é como um irmão para mim. (He is like a brother to me.)
5. Vou viajar com o meu irmão. (I am going traveling with my brother.)