Love Always Remains

Pewter is very catholic and it does impact him a lot, and Jesus DOES give his followers bread and blood for them to eat and drink as though it was his body... and Pewter worships Renju, too.

It also represents the blood that was shed for their sins, and Pewter's blame on his sins is very persistent on his somnium. Jesus also says he won't drink it until he's in heaven with them, and Pewter says he's waiting for the day he'll see Renju's smile in heaven.

It's also called "laughing sickness" which fits Pewter as he uses positivity as a form of self harm. It can be contracted through cannibalism, which brings us back to the idea of him eating Renju's body.

Random outbursts of laughter, emotional degradation... That's just his somnium! Not to mention that it can take up to 50 years to kick in, he could very well have prion disease in canon already.

"Emotional instability and depression, yet exhibits uncontrolled and sporadic laughter." Very literally his somnium.