What is the ruling on a husband being affectionate, spending evenings, and conversing with his wife; is it obligatory or a matter of favor? And what are the etiquettes of a guest that the wife's brother must observe?

Part of good companionship is to be kind to one's wife, sit and talk with her, and show interest in her, while balancing this with other concerns so that one aspect does not overshadow another.

As for the etiquette of a guest, it includes leaving after eating and not staying for a period that would cause discomfort to the host, in accordance with the Almighty's saying: "And when you have eaten, then disperse, without lingering for conversation."