He hasn't known Will for very long, but he's very familiar with the other boy's tendency to put everyone else before himself, to literally wither away before leaving anyone untended or inconvenienced. It sounds like Will has adopted some accommodations to make his time in Nocwich less hazardous to his health, so Wilhelm won't harangue him about it. He'll just keep an eye on his friend to make sure he's not on the brink of passing out.

"Let me know if you need an emergency doughnut, okay?"

Sugar had seemed to do the trick last time, like it was a sunlight substitute.

Stretching his arm out to give Will a better look at his tattoo, he continues, "Frogs go through metamorphosis. At different stages of their lives, they look like completely different creatures." His eyes trace the lines of the frogs inked into his skin. "So...I thought it was fitting. I'm not the same person I was when I got here."