Miriam dies in Chapter 20. She is buried and suddenly there is no water. Hence the tradition that Miriam’s well followed the people until she died. But otherwise no mourning rituals are mentioned.
Aaron died soon after in the fortieth year after coming out of Egypt. His death was very public and moving. Moses slowly stripped him of the garments of the High Priest and transferred them to his son and he was buried on the mountain called Hor (Hor Hahar can mean the Mountain of Hor, or Hor of many summits). And the people mourned him for thirty days.
Not long later when Moshe dies the Torah specifies ” Moses the servant of the Lord died there in the land of Moab, according to the word of the Lord He buried him in a valley in the land of Moab, opposite Beth-Peor; but no man knows his grave till this day.” And he too was mourned for thirty days. These two cases are the only mourning rituals mentioned after Sinai as defining Jewish practice.
What was the difference between Aaron’s burial place and Moses’s? We don’t know where either was buried. On the other hand, the Cave of Mahpela where Abraham, Isaac and Jacob were buried is recorded and we believe we know where it is even now. What is the difference? One answer is that because Moses and Aaron were buried outside the Land of Israel God did want us to go on pilgrimages beyond our borders.
But there’s another lesson. Our tradition says that God did not want people to know where Moses was buried so that people would not worship him or his grave. How different from nowadays when we seem to have a very fetish of going to the graves of dead rabbis. If we were not supposed to go to Moshe’s grave how much more so should we not go to lesser beings?
Moses gave us the Torah. It is Torah must be the object of our focus. God wanted us to think of Torah rather than the human vehicle who brought it to us. Moses is called our teacher. But it is what he taught that matters most. That would also explain the difference between Aaron and Moses. We don’t know exactly where Aaron was buried either even everyone saw him go up the mountain. It was up a specific mountain but that’s a huge area and very difficult to get to. But Aaron was not associated with giving the Torah to the same degree as Moses. We do not call it the Torah of Aaron. Moses on the other hand was buried in a valley, guy. As the Torah says in the last Chapter. A valley is easily accessible. That’s why we were not told where it was, so as not to go looking.
So really the Torah gives us two different ways of relating to the dead. Some prefer to visit the graves of their loved ones and some do not. Some know where to go or how to find where their parents are buried. And some nowadays would be unable to go because their parent’s graves are in hostile territory.
What matters is not the grave but whether and how we keep the memory alive within ourselves and in the way that we honor our parents and follow the good examples they gave us as human beings and as Jews.