I am Dr. Lisa; welcome to JustAnswer!.
You are describing classic signs of malnutrition, and specifically Hypovitaminosis A. However, this problem can also present the same as fungal disease foremost, and secondarily as parasitic, viral or bacterial respiratory disease, in addition to the malnutrition (discolored feathers).
I would guess that Bruce eats a seed-based diet. If that is the case, he needs to be made healthy and switched over to a high quality pellet. Before you can safely do that by yourself, he needs to see an avian vet (www.aav.org/vet-lookup) ASAP in the event that a fungal granuloma s causing his wheeze and breathing problem.
In the interim, could you put him in a makeshift hospital cage/brooder with a padded bottom, and low/no perches (in the event that he weakens and falls),increase the temp. to 80F/27C and put his favorite foods and water close by?
If you do not act quickly I am, afraid he may not make it, but if you act immediately he has the best chance of a full recovery.
There are no safe or effective OTC products to use.
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