Towing: Is a 1Ton 5.7L gas Chevy ok to tow 10,000 lb 5er?

My neighbor has a 99 with the 5.7 and 4.10 gears. He is pulling a 10,000# FW, and says it has no power, even on the level roads. It takes so much gas, especially in any wind, that he no longer pulls more than 50 miles out. He is pulling an 04 Hitchiker, with a tall, square front.

Jerry