I am thinking if the bedroom and basement get zero heat, likely a flexible duct is ripped open, or disconnected. If this happened close to the source, it would slow air flow to all registers.
My FW has 4 main registers, plus the small duct to basement. I only have one floor vent, and the rest go through various cabinets. I can see most of the flex duct, which is routed to keep lines, and water pump from freezing.
All my vents blow similar amount of air (testing with hand). IMO, the air flow is substantial, and can be felt several feet from vents.
Jerry