Information about (possibly) getting a Council Tax reduction can be found here:
https://www.citizensadvice.org.uk/housing/council-tax/check-if-you-can-pay-less-council-tax/
From that page, note that it's the 'working age' rules that will continue to apply if either or both of you continue to receive income-related ESA, not the 'pension age' ones.
Further, note that each council has its own scheme for Council Tax reductions. There's no national scheme, so the rules will differ across the country.
Wherever you are though, it's worth applying anyway. (As long as you're entirely truthful on your application, you won't be committing fraud. The very worst that could happen is that your application could be turned down).
If you're in Sheffield, as I think that you might be from your previous posts, you can make an online claim here:
https://www.sheffield.gov.uk/content/sheffield/home/benefits/council-tax-support.html