At the time of passing, nothing accompanies a person: neither silver, nor gold, nor gemstones and rubies, only Torah and good deeds!
The most effective thing you can do to elevate a departed soul is study Torah – particularly Mishnayos (Mishna has the same letters as Neshama).
There are files of elucidated Mishnayos here, for your convenience – you can also print them.
May we merit to see the fulfillment of the prophet Yeshaya’s vision:
“He has eradicated death forever, and Hashem Elokim shall wipe the tears off every face…” (Yeshaya 25:8)
Type in the name of the niftar, click on: “Download Mishnayos”, and get a file with Mishnayos compiled according to the name of the deceased.