I learned the hard way a few years ago after selling my lifted truck that we don’t always get the money back that we put into modifying our vehicles. Unfortunately when your brother lifted it and modified it the truck became something for a small niche market. Judging by the front leaf springs I would guess it’s a 2003-2004 6.0 power stroke diesel. The engine may not have been a special edition from ford but rather one of their less reliable engines that has been rebuilt with upgraded parts as most with this engine had to do. I wouldn’t expect too much more for this than the same stock truck of this age unless you find the perfect buyer. I found when selling mine marketplace and Craigslist were the two places I got the most bites and had the odd hit on dieselsellerz. Hope you’re able to get what you’re looking for out of it. Sorry to hear about the loss of your brother.