Can a relative who is not a close family member sponsor my visa by providing income tax returns in Ireland/Australia?

No, a relative who is not a close family member generally cannot sponsor your visa by providing income tax returns in Canada, Australia, or Ireland.

Visa sponsorship in these countries is typically limited to close family members such as spouses, parents, children, or sometimes siblings. Income tax returns from distant relatives like aunts, uncles, or cousins are not accepted for sponsorship purposes.