He had a long life and there are lots of great stories about him. Everybody and there uncle tells stories about how beyond great their teacher's teacher was, so I'm not going to do that even though I think it's true.
He was a performer of Beijing Opera in his early days, playing the lead roll of Monkey King. He was also a serious contender in matched fights and as the story goes, he quit because people were sneaking up to him in the middle of crowds trying to get close enough to slice one of his tendons with a razor blade.
He studied baguazhang with the second generation. He also studied with Wang Shengzhai during his early days. After the war he fled with the Kuomintang. He taught Northern Shaolin, Yiquan, Xingyi, Guanping Yang Taijiquan, lots of weapons, a little Bagua, and one person learned a little monkey gongfu, but he has since forgotten it.
He work as a bodyguard in Shanghai, and had extraordinary skills with a rope dart. He kept the rope tied around his body and was capable of throwing it without the use of his hands. Several of his students have described being quickly tied up against their will. I ran into Kimo the other day, one of his students from 40 years ago, and he told the story of how he, Kuo and my teacher Bing Gong, were performing at the old Emporium in San Francisco, which had high cavernous ceilings with wooden beams. Apparently he laid his rope dart on the ground (the dart was made out of a piece of a tire iron) and then kicked it straight up in to one of the high beams, where it stuck.
It seems he taught less than half of what he knew. Why?
He clearly had something of the secrecy that verges on paranoia common to many "masters." When he began his studies it was still illegal to publish a book on martial arts; the Boxer Rebellion, the civil war in the 1880's, the collapse of an empire, these all may have played a part in his thinking.
But he was ahead of his time in deciding to teach Westerners, so he was also open to new ideas. It is possible that he simply felt he had no qualified students; that even his Chinese students had not even a glimpse of what it required to learn gongfu in his day.
If his students had been only interested in fighting he would have taught them even less.