Is it permissible for a maternal uncle to perform 'Umrah on behalf of his living mother who is financially unable to perform 'Umrah? And is it permissible to perform 'Umrah or Hajj on behalf of living individuals who are financially or physically incapacitated? And must the proxy be a relative or a mahram?

For the代理 (niyabah) to be valid in Hajj or Umrah on behalf of a living person, two conditions must be met: the person must be physically incapacitated in a way that is not expected to recover, and they must grant permission for the proxy. Additionally, it is required that the proxy has already performed Hajj or Umrah for themselves. It is not a condition for the proxy to be a relative of the person on whose behalf the pilgrimage is performed.

The obligation of Hajj and Umrah is contingent upon financial capability. Therefore, whoever is not financially capable is not obligated to perform Hajj or Umrah.

Based on this, if the mother does not have the financial means, Hajj and Umrah are not obligatory for her. It is not valid for her brother or anyone else to perform the pilgrimage as a proxy for her, unless she is physically incapacitated in a way that is not expected to recover.