If the monetary system collapses within 10 years and BTC ever reaches 10 million dollars, he will have a net worth of 1 400 000 000 000 USD. Aside from his other assets that I'm not aware of.
If we think logically, if the monetary system collapse, then there isn't be fiat standing on an economic system which means we can't compare BTC with USD, EURO, YUAN or another fiat, which means BTC=BTC. We can able to compare BTC with goods, foods, houses, gold, and others. A question, have Saylor become rich?, I don't think so, because we still have Satoshi and others (anonym) who have Bitcoin more than Saylor.