He is making millions of illegals legal. Changing the law.
Onus is on you to prove that he has "changed the law" and that he is making "millions of illegals legal".
Because he is not doing either of those things.
He hasn't "changed the law" one iota. He has simply used prosecutorial discretion" which is granted to him under the existing law to decide on prioritizing deportations. The law allows that those whose cases are thus postponed can apply for work permits while they wait for their cases to be heard. All of this is current law on the books.
It is up to Congress to change these existing laws if they don't like them.