I'm sorry for the loss of your father-in-law. And I know how hard it is to handle an estate.
Here are three quick options:
1. Sell in bulk to KEH. If you call them on Monday, you can get a price for all the equipment, which you can then ship off to them. They will likely pay less than half of what they will sell it for. This is your easiest and fastest option to get rid of the equipment quickly, though you won't get top dollar.
2. Sell yourself. This requires a lot of work and time. You could, of course, take the equipment to an ebay reseller, who will sell it for you and take a percentage, but having known people who did this with non-camera equipment while settling an estate, I worry that you probably will net approximately the same amount as with option 1, and it will take longer. Of course, you can sell it here on APUG, and that would be great. But to do so, you first have to have an idea of what these things are worth. Looking at KEH or ebay completed sales will give you an idea, but note that people pay less from a private seller. Still, I know I'm looking for a simple Nikon for my daughter who's taking a photo class, and I bet I'm not the only one who'd be interested in some of the things on your list.
3. Donate them to a photo education program. If there's a local high school or college offering film photography, they may be grateful for the equipment. On the other hand, school is usually out this time of year, so you may have to wait a few months. Or you could donate them through APUG - the ads are free.