Well I don't think American will ever fly a 777 to Brussels. American will always fly 767's to Brussels. There are doubts about restarting the DFW-BRU route, I don't think they'll do it anytime soon and even if they do they won't fly the 777 on that route. The 777 is too large, a 767-200 would be enough. If the market is improving, American may switch the equipment from a 767-200 to a 767-300 but not to a 777.
About the ORD-BRU flight, the outbound flight out of ORD will continue to operate in its current schedule, that is leaving ORD at 845PM and arriving BRU at around 1200N, but the return flight may leave one hour earlier and arrive ORD at around 400PM instead of 500PM so that passengers can catch connecting flights more easily. Right now the aircraft is a 767-300 but it may at any time be switched to a 200, you never know.
Always SEVEN SIX SEVEN.