"and be gathered to your people": with Abraham, Isaac, and Jacob, your fathers; with Kehoth and Amram, your fathers; with Aaron and Miriam, your brother and sister.
"as Aaron your brother died": the kind of death that you desired. Whence did Moses desire the death of Aaron? When the L-rd said to him (Bamidbar 20:25-26) "Take Aaron and Elazar his son … and strip Aaron of his garments," they stripped him of the priestly vestments and put them on Elazar … He said to him: "Enter the cave"; he entered. "Lie down upon the bed"; he did so. "Stretch out your arms"; he did so. "Stretch out your legs"; he did so. "Close your mouth"; he did so. "Close your eyes"; he did so. At that time Moses said: Happy is he who dies such a death. Thus, (here) "as Aaron your brother died" — the kind of death that you desired.