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

No.

While the word "seus" shares the same spelling and fundamental meaning (masculine plural possessive) in both dialects, there is a significant difference in usage regarding which person it refers to. In Brazil, the pronoun você is the standard way to address "you," and its corresponding possessive is seu/seus. In Portugal, the informal "you" is tu, and its corresponding possessive is teu/teus. Therefore, when expressing the idea of "your" to a friend, a Brazilian will naturally use "seus," while a Portuguese person will naturally use "teus." Additionally, Portuguese speakers almost always include the definite article (os seus/os teus) before the possessive, whereas Brazilians frequently omit it.

Brazilian Portuguese

1. Onde estão seus livros? (Where are your books?)
2. Eu gosto muito dos seus sapatos. (I like your shoes very much.)
3. Você esqueceu seus documentos. (You forgot your documents.)
4. Me mostre seus desenhos. (Show me your drawings.)
5. Seus amigos chegaram. (Your friends have arrived.)

Continental Portuguese

1. Onde estão os teus livros? (Where are your books?)
2. Eu gosto muito dos teus sapatos. (I like your shoes very much.)
3. Tu esqueceste os teus documentos. (You forgot your documents.)
4. Mostra-me os teus desenhos. (Show me your drawings.)
5. Os teus amigos chegaram. (Your friends have arrived.)