Normally, I will strengthen their spirit connection with the world (if only you want their ghost around for a while) by clicking the urn/tomb, else, you can consider to release their spirit to the Netherworld (and, they'll no longer exist in your game), if you don't like the idea of having ghost hanging around..
If you decide to strengthen the spirit connection, you'll have lots of other interaction with the urn/tomb, especially if you have a remembrance day/day of the dead in your calendar. - and it's good for the family to cope with the missing and move on after a while, because you can release the spirit anytime you want..