Well we all know that any amount is possible to reach by Bitcoin, but we can't really say how much it can take in a specific day or year. I agree with him that majority of those existing alternative cryptocurrency will fail soon because they really don't have any unique usage and most are just shitcoins, and if that happens money will pour in those coins that will survive mostly in Bitcoin so it is possible that it can hit $40000 or even more. So if that happens before this year ends, maybe his predictions are right. But the problem here is even those shitcoins will not survive, more new coins will come as long as there are people who are willing to invest.