It depends on the situation I think. If you sell now, you can wait for a dump and buy again. There will be a fork this august so it will obviously dump. That is the best strategy I think to have a good profit.
There won't be a hard fork in August, don't spread such fud. UASF is a soft fork and its looking doomed to fail anyway as it doesn't have wide support.
You can read the post again, and there you might realize he did not say hard fork but just a fork. Either way, there might be a soft fork or none, bitcoin price will be dumping because we all know many investors and users are panicking at a time like these. But if did not happen, well, that is great.