No, you cant help anyone else become any form of node as a pruned node. You dont share old blocks and in order to become a pruned node all blocks must be downloaded and verified.
Interesting. It seems that I was wrong. I was under impression that it functioned so and actually thought that you're the one who told me this a while back. So essentially if you start fresh with setting for a pruned node you have to go through everything but only keep the latest X amount of blocks? What does a pruned node relay, or does it relay nothing?