We have duties towards our dead relations and friends. November is dedicated to the holy souls in Purgatory.
First - we must bury and NOT burn our loved ones (ie cremation). This has always been Catholic teaching until the Catholic Church was taken over by freemasons at the Second Vatican Council.
This respect for the body has always been church doctrine - the dead people's souls are eternally alive,, even if they are in Hell, Heaven or Purgatory. The pagans, 1000s of years ago used to burn the dead. When the Catholic Church started on Pentecost in AD 33, this practice of burning the dead was condemned by the Church.
We are duty bound to pray for the souls in Purgatory. How do we know who is and who isn't in Purgatory? We don't know - so it helps to pray for someone and add "if it benefits so and so"
The souls in Hell can never escape, so prayers are wasted on them - as they are wasted on souls already in Heaven. However - no prayers are wasted - as they will go towards the souls in Purgatory who need prayers the most.
The good news is that - if our prayers help a soul from Purgatory into Heaven - that soul will be able to help us in turn!
I find it most alarming that people cremate their loved ones and then this hideous fashion of scattering ashes in random places. This is so sad. How will future generations visit their dead relations if the ashes have been scattered?! They will soon be forgotten as there is no grave to visit - let alone a headstone with their name on!
It's a useful exercise to write down the names of all your dead relations and friends on paper and refer to it every now and then. It's a custom in Catholic Churches to write down all the names and give to the priest - who will put them on the altar.