The way I read the original argument, from iano's perspective, the essential goodness of your loved one gets stripped away before they get sent to their torment...however that is defined...thus feeling regret for your friend being tormented is not justified, since your friend is not the being being tormented.
If I have that right, it still doesn't preclude feeling regret that your friend now doesn't exist. I mean, we feel sad when our friends/loved ones die, even if we believe they have gone to Heaven and are basking in glory and happiness, so just the mere absence of someone causes regret and sadness. If going to heaven somehow removes this from us, then we also lose something essential about ourselves, so not only is the being in Hell not your friend, the being in Heaven is not you...so in otherwords, it doesn't matter where your friend ends up, since he always ends up in the same place you do...nonexistence.
At least, that's the only logical answer I can come up with based on iano's initial argument.