Can we include dead people in our udhiyah? Fx. Parents. And if some people eat under the same roof but they have reached the nisab is 1 udhiyah still enough for that household?

Imam Ibn Uthaymeen, may Allah have mercy on him, said: “A man should offer the udhiyah (sacrificial animal) on behalf of himself and his household, and it includes both the living and the deceased. This is the Sunnah.” — from Fatāwā Nūr ʿalā ad-Darb.