There is no clear answer in the animation about whether Li Keyong has been pretending to be forced. He has always been a cripple in his stories, but that doesn't mean he has been pretending to be a cripple. In the plot, Li Keyong's physical condition is sometimes good and bad, sometimes he is lame, and sometimes he can act normally.
As for Li Keyong's death, he was killed by his adopted son Li Xingyun. At the end of the animation, in order to win the world, Li Xingyun and Li Keyong launched a duel. Finally, Li Xingyun won and Li Keyong died. But it is worth noting that Li Keyong's death was not suspended animation, but was actually killed by Li Xingyun.