The fund in question are forfeited assets not “appropriated funds” , assets seized through law enforcement actions. They fall directly under the executive branch , Anything can be done with them without any direct Congressional involvement , so yeah he did his legal homework
Discussion
It doesn't matter. Congress, not the Executive, has the power of the purse. They alone have the power to establish and maintain such a fund. I don't believe any aspect of this is good. Even if I accepted that it was somehow lawful, I still don't believe it would be good for the other reasons I expressed. Regardless of what I think, we'll all just have to sit back and see how it turns out. I hope my concerns are misguided, but that's not how I see it.