Welcome here. Those are some difficult questions, hopefully you will both come to the same conclusion. First of all, if you haven't already, I would ask him why it is that he is wanting another child. If you aren't sure yourself just yet, you really want to make sure he is completely on board for all the right reasons before embarking on a journey like this. Sometimes things happen quickly for the women here, other times it can take a very long time, if at all. If he is sure this is what he wants, then I would start by making an appointment like Susan said, even if you are still trying to make up your mind about it.
As for having another child at this point in your lives, there are many things to look at. Finances is only a small part of it to me. And no, we are not flowing with cash, things are pretty tight around here. To me, I value the gift of another child and the love that I can give them and that the child could give in return to both me and the rest of the family as being of far greater value than the cost of raising another child. In your case, I would also consider the benefit to your 6 yr old of having another sibling, especially after you and your DH are gone.
Whatever you decide, I hope that you are both able to completely agree with the decision. Do keep us posted on how you are doing with it all, and we are here for you if you do decide to go for it.
Loving Mom to three
Loving Mom to three rambunctious