Are their money issues due to a mental impairment? If so, seeing a doctor and getting it diagnosed could help. If it is severe enough they could apply for attendance allowance and apply for a severe mental impairment exemption. But that really depends on what a doctor says.
Council tax reduction is through your local council here https://crawley.gov.uk/council-tax-and-benefits/about-council-tax/council-tax-reduction. There are also benefits calculators they may be able to use to see what they may be entitled to. Some can be found on the government website at...