Can a sibling sponsor us on a fiancee/spouse visa?

[Nick30]

Hey all,

As I was saying the other day about moving on to Europe and coming on European law, I just knew now that I'm exempt from this new rule as I'm on DLA
We plan to stay at my brother when we apply for fiancee or spouse visa.
Can my brother and sister in-law sponsor us?

Thanks in advance

[Nick30]

I forgot to say that I don't have a place of my own.