Dusty - good on you for making sure that this is a topic that is out there between the two of you. My only comment on your DH belief is - would he be able to donate your organs given the circumstance arises?
I would donate all of my organs Except for my eyes - it is really strange i know but it is something personal really - my sister is of the same stance and i take consolation in the fact that as i need glasses i am sure they would never harvest my eyes anyway! - also i would not save someones life, just their vision, which i know is important though.

As a Nurse i have seen many many people die - Oie made the comment that she thought that your soul would pass on at the time of death... Now i am not of any real religion but i can tell you that when someone dies, something leaves, it is very obvious when someone passes as although their physical body is there, the person seems to be no longer there... Families often comment that they look so different when there is no life left.

To another note - there are sooooo few opertunities that a person can actually donate, pretty much you have to be in a hospital when you die so that you can be placed on life support so that the heart and lungs etc continue to function so that they are not damages by tissue death prior to collection and transfer. Also if the circumstances of death are suspicious you cannot donate as you would need an autospy... Cancer sufferes very often cannot donate some or all of their organs and people that are having certian treatments also cannot. That is why so few donations are actually made as you have to be in the right place at the right time (thats sounds awful doesnt it)

Also to follow up on the tests that are performed to determine brain death they are very strict and i am doubtful that an error would be made nowadays.
We often suggest switching off the 'lifesupport' as chance of survival is slim, but this does not necessairly mean that the person is actually brain dead - if that makes sense
I hope this helps