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

Yes

The word "coisas" is identical in meaning, spelling, and grammar in both Brazilian and Continental Portuguese. The only difference lies in pronunciation. In Brazilian Portuguese, the "s" at the end of the word is typically pronounced as a soft [s] (as in "sun"), and the vowels are more open. In Continental Portuguese, the "s" is pronounced as a postalveolar fricative [ʃ] (as in "shoe"), and the vowels are more closed or reduced, often making the word sound shorter and more clipped.

Brazilian Portuguese Examples

1. Eu tenho muitas coisas para fazer hoje. (I have many things to do today.)
2. Não me diga essas coisas. (Don't tell me those things.)
3. Ele gosta de coisas estranhas. (He likes strange things.)
4. Vamos organizar as nossas coisas. (Let's organize our things.)
5. Tem muita coisa acontecendo por aqui. (There is a lot of stuff happening around here.)

Portuguese (Continental) Examples

1. Tenho muitas coisas para fazer hoje. (I have many things to do today.)
2. Não me digas essas coisas. (Don't tell me those things.)
3. Ele gosta de coisas estranhas. (He likes strange things.)
4. Vamos organizar as nossas coisas. (Let's organize our things.)
5. Há muita coisa a acontecer por aqui. (There is a lot of stuff happening around here.)