is friends with

[simonaj]

I've read this sentence: "My second cousin is friends with him and his wife". is this line correct?

 

[maxiogee]

Yes.
I think it seems worse than it is.

 

[iFeXx]

Yep, it's frequently used.

 

[panjandrum]

Goodness!
I've never thought about this before, but it does seem a little strange.
Strange or not, it's been used for a long time:
1596 SHAKES. 1 Hen. IV, III. iii. 203, I am good Friends with my Father, and may do any thing.