No, not possible to declare a dependent years in advance.
IF when you file your 2022 tax (in 2023) AND your son is under age 24, is a full time student, and lived with yiu more then half the year (or would have lived with you if not temporarily away form home to attend school), and does not support himself, then he would qualify as a dependent.
However, that is 2 years in the future so there is no guarantee that tax laws will be the same.
**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**
