Quick question: I see nothing in the manual for tire pressure which is key for proper mowing.
Pressure?
I don't have any of my material handy, but using 20 lbs in the rears and 25-30 for the fronts can't be too far wrong. Also can use the "ground contact" method: With the tractor fully loaded and on a flat, level surface, inflate each tire so the tread makes contact across its full width, without any unnecessary sidewall bulge.
Sorry to hear about your BIL, our thoughts go with him.