As the correspondent explained:
My son says the parties are full of eastern "spirituality" and he's been warning his friends who go to them about the avodah zora aspects of them.
He says they "worship the speakers" or something.
They don't mean it to be avodah zora, but it's not good.
As is now self-understood, that refusal to attend the party for the sake of Shabbat saved that young man's life.
So many people saved their own lives by either not attending the party at all or leaving before Shabbat!
Yet the brother of another friend did attend the fateful party.
Afterwards, no one knew where he was.
One night shortly after, the father of the missing boy had a dream. As the correspondent describes it:
...his father dreamed that his son was holding a golden sefer and he said, "Don't worry, Abba. I'm learning Torah with Hash-m."
Who Knows the Cheshbonot of Shamayim?
Yet from the accounts of the people who knew them well, we can glean indications regarding their last moments, that some managed to do some kind of teshuvah or some kind of kavanah to die al kiddush Hashem (for the sanctification of God's Name).
And we know from great tzaddikim and talmidei chachamim like Rav Yehudah Petayah, that even a split-second thought of teshuvah the moment before death still holds tremendous power for atonement in the Next World.
(For more on that topic, please see here: minchat-yehudah-part-i-teshuvah-and-what-happens-after-you-die.html.)
In conclusion, let's take comfort in the words of the Me'am Lo'ez on Parshat Beresheit (page 184):
If a person has been killed by the gentiles, his image is engraved on [the angel's] vestments, and [the angel] brings it to the highest heaven.
There, this person is recorded in the Great Book.