After he bought twitter shares he only had to disclose that he did so with the SEC that was it. He did that late.
None of this requires making an offer for acquiring twitter. But that’s what he did he made an offer to the Twitter board for 44B$, after the Twitter board realised it didn’t appear to be a joke they accepted the deal.
At this point nothing was signed, this was the time before confirming the merge deal to do his DUE DILIGENCE which he didn’t do, he was in his right to back out at this point.
Instead he signed the contract and only afterwards realised he didn’t want to pay 44B$ for twitter after all. This was already too late and nearly impossible to do, the deal was signed…