decrease_helped_landed_sibling_value_effect

decrease_helped_landed_sibling_value_effect = {
	hidden_effect = {
		if = {
			limit = {
				root = { is_ai = no }
				has_variable = helped_landed_sibling
				var:helped_landed_sibling > 1
			}
			change_variable = {
				name = helped_landed_sibling
				add = -1
			}
		}
		else = {
			remove_variable = helped_landed_sibling
		}
	}
}

As written in game/common/scripted_effects/00_sibling_effects.txt.