How is "peace" conveyed from one person to "the small family"? And must peace be conveyed to every member of it, or only to the parents? And is one sinful if they do not convey peace, whether intentionally or forgetfully?

It is recommended to send greetings (salaam) to an absent person. The one entrusted with delivering the greetings must convey them to the intended recipient, based on the words of the Almighty: "Indeed, Allah commands you to render trusts to whom they are due." Otherwise, they would be sinful if they deliberately failed to convey them. If they forget, there is no sin upon them. It is sunnah for the messenger to respond by saying: "And upon you and upon him be peace and the mercy of Allah and His blessings." The messenger delivers the greetings to everyone or to those specifically intended by the greeting. However, if there is a non-mahram woman, one should not offer her greetings if there is a fear of mischief.