It seems to me that his calculations are based on the fact that after halving, Bitcoin price should start to grow faster and on the whole cryptocurrency market should start new, much longer and several times larger than the last bull run. Theoretically, Altcoins prices should start rising with the price of Bitcoin.
However, this is only a very optimistic theory. It is enough that something unexpected happens and the bear market will last another two years. Anything could happen.
in any case with halving, the situation in the price will change, but do not forget that, if desired, any states or billionaires can change the price as they like
Until market capitalization increases whales will definitely try to manipulate the market. However, notice that halving will reduce the "reward" for finding the block by half, and this is once again. At the beginning reward was 50 BTC, now it will be only 6.25 BTC. This will reduce the supply on the market, and let's not forget that demand is still growing. The price just has to go up.