Even if he has to give up the apartment and move back home if he goes to college (I totally forgot why there's no good college anywhere close to this apartment, but let's just suppose that for a moment), does that really mean that he also 100% has to be apart from Akutsu-san?
Akutsu-san is covertly listening to all that reasoning and thus she may just enter and say that she would follow him back to his home and they'd live together somewhere close to his college or (let's be reasonable) at least somewhere where the apartments are affordable and the commute to that college is not a total hell.