My 16 month son has Tay Sachs Disease

I found out yesterday that my son has the rare rare rare Tay Sachs disease. There's less than 20 cases a year, mostly in Jewish bloodlines which we aren't so it's even more astounding. He had all the symptoms but we were hoping he would have something that can be treated. He was completely meeting milestones till month 8 then had regression.

The next symptoms include seizures, blindness, deafness, unable to eat, unable to breathe. The life expectancy is by age 3.

What should I do? I can't handle this my husband and I do everything. He graduated med school and he gave that up and stayed at home with him since noticing the regression. Now we are going through the biggest tragedy of our life.

What do you do when you know you child won't make it? How can I be strong and fight for him when I'm dying inside too?