He’s triggered the consultation requirement, and (shortly) the 48 hour notice requirement, but I don’t think he needs approval. They can vote to shut off his funding, but he could keep fighting with his “stash”.
The anti-war left must be tied up in logical knots at the moment. We’re going to war, but we’re doing it to save members of one of their protected classes.
Why not, the War Powers Act seems pretty clear that he needs prior approval unless America is under attack or under a serious threat. Neither exception applies in this case.
It's an impeachable offense, if he does it without their approval. However, I think a resolution reprimanding him would be more likely to be successful and avoid letting him set a new precedent.