I am sorry for your and your DH's loss . But, perhaps your DH has a new brother. They can have DNA studies done to confirm. This may turn out to be a wonderful blessing. And maybe this 17yo needs to have an older brother to help into adulthood. It is very common that when someone dies you find "surprises" hidden in the back of the undie drawer. When my grandmother passed we found that she had been married before and had lost a set of twins. It may not be about the money, or things. They may just need some support and love too.