A lot of people don't read fiction in search of realism. They do so for escapism. If the boring or miserable parts of real life show up in that escapism, it tends to rub a lot of people the wrong way.
I'm giving this manga 2 more chapters to clear things up. Because this has gone on for more than two months of our time. Either the mangaka is winding down for a finish or they're dragging the story out.
Pardon, but it is 'thine umbrella' and 'mine/my umbrella'
I get it though. Possessive articles are the trickiest bit of Early Modern English or Elizabethan era English.