If the court ultimately rules that he’s acting within the scope of the National Emergencies Act, then the only thing they could do is repeal that act by a veto-proof vote - and there’s no chance they could do that.
It’s not a repeal. Congress (under a
national emergency declaration) will
meet every 6 months after declaration
to try and pass a resolution to end it.
If Trump feels the resolution doesn’t
fix the problem, he can veto. They can’t
simply vote just to end it.
“A national emergency can be terminated if the president issues a proclamation or if Congress enacts a joint resolution terminating the emergency.”