A thought that appeared thanks to dot's post about Tomix
What was on his mind when he made that MSW coat for Hero? Did he think about the Hero who flinches from the cold? So he made sure the coat would cover them from top to bottom. Did he feel guilty? For hiding the fact that his time is so close to an end and he hid it from everyone, even the one he trusts most to keep an eye on his back. Did he feel he's being cruel for leaving them he coat when he'll be gone after everything? Maybe there are so many thoughts on his mind as he made that coat little by little, maybe doubting himself. Or maybe not. Maybe he's happy either way, at least even after he's gone he could help his friend indirectly, at least he could help them against the cold with this coat.
Or maybe he feels proud, because I assume Hero is his first student and probably even the brightest one. Maybe if our Hero is a soulweaver main long after he taught them he's more than happy to know that what he knew and what he taught has been used for good. He knew he could trust the Hero because they are after all a Hero. Because, of course, meeting Hero, befriends them, and even teaches them have become the One Good Event™ for him
Who knows whether he'd have the chance to actually see his student, his friend, his trusted ally with the coat that he made, as long as he can give them the coat, that'd be enough. Maybe the coat was made with so many conflicting emotions, but in the end all of them were proof of his care and love for Hero.