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

No

While the literal meaning (old) and the spelling of "velho" are identical in both dialects, there are significant differences in typical usage and slang.

In Brazil, "velho" is frequently used as a casual interjection or filler word, much like "dude," "man," or "bro" in English. It is used to express surprise, frustration, or simply to address a friend. It can also be used affectionately (e.g., "meu velho") to refer to a father or a close male friend.

In Portugal, "velho" is strictly used to denote age. Using "velho" as a casual interjection to address someone is not natural; instead, the word "pá" is the ubiquitous equivalent. Additionally, when referring to elderly people, Portuguese speakers often prefer the more polite/formal term "idoso" rather than simply calling someone "velho."

Brazilian Portuguese Usage

1. Velho, você não sabe o que aconteceu! (Dude, you don't know what happened!)
2. Aquele cachorro velho é muito calmo. (That old dog is very calm.)
3. E aí, meu velho, tudo certo? (Hey, my old buddy, everything alright?)
4. Ele é um homem muito velho. (He is a very old man.)
5. Velho, que frio é esse! (Man, what cold is this!)

Continental Portuguese Usage

1. Pá, tu não sabes o que aconteceu! (Dude, you don't know what happened!)
2. Aquele cão velho é muito calmo. (That old dog is very calm.)
3. Olá, meu caro, tudo bem? (Hello, my dear friend, everything alright?)
4. Ele é um homem muito idoso. (He is a very elderly man.)
5. Pá, que frio é este! (Dude, what cold is this!)