Grammar
N3AI-drafted〜まで(意外)
even ~ (surprisingly)
Formation
N(+助詞) + まで
Usage
Here まで is not about time or place limits but adds an unexpected item to a list, showing the situation has gone further than expected. It often expresses surprise, dismay or criticism, as in 'even my own family doubted me'. Close to さえ, but まで suggests an added, escalating extreme rather than a minimal example, and it is usually used with affirmative statements.
Examples
弟にまで笑われてしまった。
おとうとにまでわらわれてしまった。
Even my little brother laughed at me.
あの店は料理だけでなく、飲み物まで無料だ。
あのみせはりょうりだけでなく、のみものまでむりょうだ。
At that restaurant not only the food but even the drinks are free.
忙しい先生にまで手伝っていただき、申し訳ありません。
いそがしいせんせいにまでてつだっていただき、もうしわけありません。
I'm sorry to have even you, a busy teacher, help me out.