Thanks all,for your comments. I'll pass the manual along to him. I don't know what his plans are for it(keep or sell). It's a serious piece of equipment.....looks to be in VG mechanical condition.
Sammy, The D-250 is a very heavy built machine, but they do have a weak point. In 1976 Wheel Horse contracted Gutbrod a German tractor manufacturer, to build their own 2500 as the WH D-250 and Wh imported 100 tractors that year. The tractors started having issues while using ground engaging equipment. The reason was the rear end is a worm gear drive and if the main carrier bushing have any wear in them, the axle will not mesh well with the worm gear and being made from a soft bronze material as most worm gears are, they had a lot of massive failures. They didn't make it assessable to to check and maintain the rear end oil, so it wasn't keep at proper levers and caused a lot of these failures. 1978 saw improvements in the rear-end, but by then people that had the 250 didn't want to spend $5,000.00 on a tractor that had such a bad rap. In total, WH imported 1,000 tractor in 1976 and 500 more in 78 and 79 respectively.
My D-250 is a 1976 model that I bought for very little and it had a WH loader on it, but the engine has been seized for years and I think it has been water frozen a couple times. I haven't decided what to do with it as I would like to restore it but I won't been able to use it as a loader/worker tractor so it may get a diesel conversion and a heavy hydro unit put in it.
I would like to see photos of your friends D-250 if you can post some. If he needs any help, I have made some contacts across the big pond to locate parts and info of these. Good Luck.