Consider the danger he will be in just prior to release. Perhaps Lin's tweets are meant to keep POTUS safe by basically informing the Deep State that he (Lin) has everything Trump has, and if anything happens, multiple other people are primed for release.
This warning is not just a warning from Lin but also a warning that people other than POTUS know EVERYTHING.
Thats my point. He knows but the moment he starts to move towards declassing that info is when it gets dangerous.
Lin is letting them know that HE and others know - presumably if something happened to POTUS Lin is basically saying he and others can drop the goods.