I am very sorry to hear how he is doing.
What you are describing sounds consistent with possible vestibular disease. The most common symptoms can occur in any combination and include: head tilting, walking in circles, vomiting,
fast eye movements back and forth (nystagmus) or the eyes pinned to one direction (strabismus), and/or drunk-like walking
Generally, vestibular disease is caused by either:
Central disease which includes anything within the brain. Or, Peripheral disease which includes problems outside the brain like inner ear infections, toxin exposure, organ problems
So, definitely, he needs to get in to a vet, and I would recommend against taking a wait and see approach. Also, I am confident we don't have any good options for at home care. Well worth a vet visit, and the vet should recommend at least a basic blood and urine test to screen for the easier to diagnosis issues in the body, as opposed to, problems in the brain.
Wish I could do more but I hope that information helps.