Struggling with a friend's expectations

Assalamu alaikum everyone, I could use some advice about a situation in university. There's a brother in my clinical rotation group who lives nearby and sits next to me in all our classes. For three years, I've been assisting him by lending books, explaining topics, and inviting him over for exam prep, all for the sake of Allah, with no issues initially. The challenge is that he now sees me as his closest friend, but as someone who prefers a small circle, I don’t share that view. He doesn't have many other friends at uni, so my help made him think we’re besties. Lately, his constant nagging, off-topic jokes, and endless questions have become overwhelming, and he even expects my help with minor tasks he can easily handle himself. I don’t want to hurt his feelings or displease Allah, but I really need my space. What’s the Islamic take on this, and how can I kindly set boundaries without being harsh? JazakAllah khair for your advice!