Sister-in-law's husband used to live outside, brother-in-law took advantage of this

Sister-in-law's husband lived in the city to work, sister-in-law and brother-in-law lived alone in the village, the brother-in-law thought of taking advantage of this, he said to sister-in-law, we both live alone here, you must also be bored and I also get bored, why don't we both have sex.