I think you've done all you can do at home without diagnostics, I'm afraid. Aspirin should also only be given, at maximum, every 12 hours. If he has not improved with aspirin alone, it's likely that prescription medications will be a better choice for him (canine safe NSAIDs, pain management, etc). Unfortunately, it's very likely given his age that the limb swelling is due to something other than just arthritis. We must consider underlying concerns like heart disease, high blood pressure, infection, etc. The fact that he has not produced urine or stool in regular intervals makes me worry underlying organ dysfunction might be to blame such as kidney failure. He's also rather uncomfortable, as we know, with him not wanting/not able to rise and offering to bite if handled.
If you cannot get him up and to the vet, consider contacting a mobile service to come to you. They work with even aggressive dogs who might be in a condition such as this. Bloodwork and x-rays are offered by some mobile services and they should be able to take a temp and determine how abnormal it is. From this, they will be able to suggest treatment on what can and should be done for him.
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