A relative who works in a bank, invites me for meals and also gives presents.

Answer

It is not permissible to work in banks. Banks are the worst institutions of riba. Do not accept the gifts of people who work in the banks. Their earnings are contaminated. Explain to them politely the reason for not accepting their gifts. In so doing, you will be fulfilling your duty of providing naseehat to your relatives. Do not be concerned if they take offence. Be concerned with Allah's Pleasure and displeasure, not with what others think and say. It is not permissible to maintain good relationships on the basis of Allah's Displeasure. Furthermore, it is always the criminal/ transgressor who severs family ties. The one who upholds the Deen does not sever ties. He only proclaims the Haqq of the Deen.