black2cat
Are you sure that it is Carers Credit that you want to claim and not Carers Allowance?
www.gov.uk/carers-allowance Claiming either of these benefits should not result in your husband's benefits being reassessed.
If you claim Carer's Credit then there will be no impact on his benefits.
If you claim Carers Allowance then his ESA may be increased as a result.
Gordon