Update - lost caterpillar (4th instar)

This is an update from my post from yesterday

Sadly, the little guy didn't make it.
After reading here and elsewhere online, I think that the poor thing was possibly first victim of a sibling's bite (which caused the initial fall on the ground), but then there was also an anal prolapse (I noticed it last night).

I feel quite sad and discouraged. It all started with about 7 eggs on my plant, then only three made it to 2nd instar last week, and now there are only 2 (4th instar at the moment). I hope with all my heart that they'll make it to butterflies, but there are so many steps still ahead and all of them full of potential mishaps, that I'm scared everytime I check the enclosure.

Initially, I wanted Nature to do its thing and had no intention of interfering, but when more than half 1st instars were lost, I got an enclosure to protect the survivors. So it's hearbreaking to have lost one more. How do you all manage to cope with all the possible lethal issues (parasites, predators, infections, malformed wings, anal prolapse, cannibalism, and what not) that afflict these critters? So far it's been quite hard for me.