The Class III Boomers historically have not needed the additional relay modification to fix the Fuse 2 blowing issue. He either still has a safety interlock switch (ignition switch, parking brake, seat, PTO) that isn't functional, a loose wire between these components, a shorted wire between these switches that caused his initial fuse to blow, or his fuel solenoid is failing and is drawing too much current.
Just as an aside, the TC40DA wasn't sold until October 2003. I suspect he doesn't have a "2001 TC40DA", but rather has a TC40D. That model initially had a 7.5 amp fuse #2, that was replaced with higher amperage circuit breaker somewhere in the manufacturing cycle of that tractor.