I recently went through something sort of similar, though not the same. I don't want to try and compare the loss as there were no children and he was actually my ex, though only by a matter of weeks. We were still financially 'linked' and so I've had to do a lot of the stressful sorting out, even though I was not his next of kin.
Unless you have particularly awful inlaws or friends, the funeral WILL be beautiful. When all the people that loved a person gather together, it almost doesn't matter what else is around.
The thing that keeps catching me out is when I read or see something I know he would have had any opinion on. I keep going to text him. At first it made me cry, but now it's starting to make me smile, although I still sometimes get a little shock when I remember.
Yours is a different, and much tougher, situation, but in the first few days I thought I'd never be able to do anything again.
I hope you don't think I'm underplaying your loss, but I just thought it might help to hear from someone who has (so far) managed to hold it together.
Please take care.