Not trying to add insult to the injury, but for the future, here are few additional options:
- wait for a schedule change to happen - very likely for November travel. That allows you to make changes w/o paying a fare difference
- as mentioned already, you could have considered a separate ticket to EWR with a much longer layover - although that brings its own risks
- did you explore if flying whY in the DC-EWR segment would have been an even exchange? Short enough flight to slum it in coach
- SDC is always an option, but that is of course subject to availability
Of course you also realize that UA doesn't have any wheelchairs, not in TLV or anywhere. They request them from local providers and at times there are issues with that; limited # of folks doing this and stuff is getting backed up. If your expectation for continuing to fly UA is reliant on non-UA services, so be it, but no other airline will be able to meet your requirements.