Here is one technique:
Take the bones and smash them with a hammer (or cut into 1- inch pieces with a bandsaw). The idea is to expose as much of the interior of the bone as possible. Then take the fat and rind and cut into 1-inch cubes. Toss these into a heavy bottomed pot and cover with 2-3 inches of COLD water - bring to a boil and then reduce to low - cover and simmer for 12-48 hours (replacing water as needed with boiling water). The longer the simmering time the greater the extraction - but 12 hours will give good results. When done - allow to come almost to room temp, strain through a fine mesh strainer and a couple of layers cheesecloth ... discard the solids and refrigerate the liquid overnight.
The next day ... you will have a layer of jellied pork stock on the bottom and a layer of rendered pork fat on the top. You can use the "jelly" any place where you would use a good pork stock ... it's good for terrines or pork pies, etc. where you want the jelly quality. The fat can be used for cooking where you need fat.
Show honor to your Father-in-law ... ask your wife how her father did it and what he used it for.
"It ain't what you don't know that gets you in trouble. It's what you know for sure that just ain't so." - Mark Twain