The best advise is the first reply in the tread. Do not sell all... do it gradually.
If he is looking out to take advantage of the huge FOMOs, then he should be considering some long term holding and trading and not the day or short term trading.
No one can know when a market can get pumped, but the best is never to get greedy as long as you have made some good profit, otherwise, unless he wants to start considering new strategies.