Can I show documents from my relative living in the UK to cover living expenses for the visa application?

No, you cannot use documents from a relative living in the UK to show proof of living expenses for your UK student visa application.

UK visa rules require that proof of funds be in your own or your parents’ (or legal guardians’) bank accounts, held for at least 28 consecutive days before applying. Funds from other relatives or friends are generally not accepted. If a relative wants to help, the money must be transferred to your or your parents’ account and meet the holding period rule.