Both children receive death benefits for there father but one child will stop because she's 18 will the amount pass on to the younger child?
If your child is a full time student or if she's disabled, she can still receive benefits after she turns 18. I would assume that the same thing applies to the younger child.
Be on the look out for a letter from them. They usually mail it out with more detailed info at least three months prior to your child's 18th birthday. You can also log on to their website or even give them a call if you have more questions. They're pretty good about answering them.
No - the amount is simply removed from the benefits - it doesn't pass on to the next child.