No, that is not what a trillion means. Musk's wealth is not a pile of cash stashed in a strongbox kept in some bank vault. It comprises the stock valuations of his publicly quoted companies. He's just floated SpaceX on the New Your Stock Exchange and the demand for the shares was so high their price rocketed - thus increasing the value of his own shares. But share prices can go down as well as up - look what happened to the value of Tesla's shares last year, before they eventually recovered!
To liquify this share value into cash would require selling at least a third of those shares - in other words, dismantling the very tool of production that created this wealth in the first place.