I think it depends on where you are in the mortgage. Is the interest already paid leaving just the principle or close? In that case, keep your mortgage and pay off the rest. You should really check with a good financial advisor. Remember to pay yourself first. Fully invest in your own retirement and then your children's college funds. Your goal for your children should be that they perform well enough, or you find funding for their educations. Chant with me, 'full ride, full ride.' Seriously, fully fund your retirement every year before contributing to a college fund.

Oh - I feel so sad for you! I just lost my grandma in June, and that was bad enough...
I'm sorry you're having such a bad year. No amount of money is worth losing someone you love.