Qaza Prayers

[Sardar Miyan]

It is generally believed that the Muslims who have not been able pray the five Salath on appointed times due to some reason or the other can pray as Qaza Salath afterwords.

Even though it is not mentioned any where in Quran, the Ulemas say that we
can compensate the shortcomings by praying the as Qaza prayers. Can some brother & sister throw light in this aspect? Thanks

[Sardar Miyan]

There is a permission as per Quran about leaving Saum due to illness/ old Age but have to give Fidya to poor. I do not know about if anybody can do Haj for another person due to inability to take long journey but there is no such provision in Quran to get help for missing Salwat. Looking forward for any reply. Thanks