Taken from 「イエスタデイをうたって２」
Context: One guy wants to visit a female friend (who he barely knows) while she is sick. This is their conversation when he suddenly stops before entering her house:
「一人暮らしの女の部屋にそう ほいほいと上がれるか？」
「シナコ先生の部屋には入ったくせに？」
「あいつんとこはいーの...」
As intended in the title of this question, what puzzles me about this conversation is the 「上がれる」. I get what their conversation is about, however I am unsure about what this part of the sentence means in a literal way. Is he asking her if she really wants to let other people enter her room/house so easily? Is the 「上がれる」simply passive?
I feel like overseeing something about the sentence and twisting the meaning to fit what I had in my head already.
(Further context: The girl actually has a love interest in the guy (what he knows about); however he is in love with シナコ先生, who is an acquaintance of both. The girl speaking in this conversation knows that he visited シナコ a few days ago and cared for her while she was sick.)
