Have you tried other clients? I doubt the notes are actually gone if you're writing to 40 relays
A big chunk of my notes are randomly gone, for no reason. I have almost 40 relays with write permissions, so the chances of losing notes were zero. I don't know what happened. Using nostr:nprofile1qqs24yz8xftq8kkdf7q5yzf4v7tn2ek78v0zp2y427mj3sa7f34ggjcpzamhxue69uhhv6t5daezumn0wd68yvfwvdhk6tcppemhxue69uhkummn9ekx7mp0qyg8wumn8ghj7mn0wd68ytnddakj703s8dt by the way. #askNostr
Discussion
that’s the first thing to try. He can use his public key in a nostr webclient for this purpose