It ain't gonna be easy
I wish I had better news for you.
We (Atlas) don't have any flights into BRU this entire month.
I checked ORD to Europe and there's one flight this weekend that stops in JFK (26 hours for scheduled mx) and then continues on to Prestwick, Scotland (PIK).
From there you're pretty much at the mercy of RyanAir. Or you could take a cab to Glasgow....
If you're interested, PM me and I'll send you the flight info.
Are you able to jumpseat on UAL out of ORD? Or Delta out of JFK or CVG? Continental outta EWR?
Good luck.