It does if he's destined to fall before the story ends. William is an Azazel/Moloch-tier antagonist at best (but slightly better written and is a lot more dangerous), not an endgame one, and IMO losing control of everything (prediction is either he'll die at the hands of Axel or he goes to jail, both symbolizing him finally losing control of everything) sounds like a fitting fate for him.
No, I'm focusing on what the story has presented about him, and so far nothing in the story has given any hint that he's willing to bend his principles to work with the Syndicate. Thanatos is a different matter because their characterization makes them compatible with one another, whereas what we know of the Syndicate so far makes them incompatible. Unless you give me a compelling reason as to why a man who went so far as to give his daughter disownment papers in the middle of the night because he couldn't control her is somehow working with the same faction who wants Orion to succeed in the Gem Hunt (which again is contradictory to his character given that he'd rather Orion hand over his gems to Wyatt), then my belief that the two of them working together is an impossibility stays.