I wouldn’t put too much weight on what Hendry says. He doesn’t come clean with his past performance, he’s selective and ramps his successes. Also I feel he deliberates obfuscates and complicates things for no apparent reason.
I agree, in the main. He did very well up to March when he was long bonds and short equities. Then he held onto this position (at least in bonds) for a good deal of the recent humungous rally in stocks and collapse in bonds.
His weakness is that he is so convinced about his assessment of the long term outlook for various financial assets that he tends to hold on to these assessments even when the market moves very substantially against him. In short, he allows his judgement of the long term outlook to override shorter term market opportunities.
That would be fine for a University Lecturer or financial pundit, but it's no good in the hedge fund business.