Harley
I do think it would be a great deal easier, in the short-term. And, yes, Lucifer could also become theoretical goop, if my brother were to aid me in that fight. But doing either of these things would also likely have consequences we cannot afford.
Unfortunately, the balance of cause-and-effect in this world is a delicate thing, and should be left alone, as much as I would often rather take matters into my own hands.
If someone had warned you of the direction you were heading, would you have listened? They must want to see it, or at least be willing. If they are not, nothing we say will get through to them. Rather, I believe the more they are pushed, the closer to danger they will walk.