Can husband get Dutch passport?

[somsaa]

I'm trying to find out but don't understand, his nan was Dutch, she died in 2014. He has family in the Netherlands!

You can only claim a Dutch passport if one of your parents has Dutch nationality not grandparents.

Why isn't he trying to find out himself?

I don't think so. Everything on the IND site is linked to your parents not grandparents. https://www.netherlandsworldwide.nl/dutch-nationality/becoming-dutch-national-abroad
Did his mother or father take Dutch citizenship?
Dual citizenship rules are also really strict in the Netherlands and often you have to give up your original nationality.