New to apartment living

I am downsizing and moving to an apartment as I am mostly an empty nester. I say mostly because my youngest is in college two hours away and only comes home for breaks which he then splits between his dad and me. He lives and works at his own apartment during the summer in his college town.

The leasing office knows about him because I specifically asked about him staying there with me for multiple days and he is fine. The issue I’m having is they will not issue him a key. I am at work sometimes when he gets home from school and I’m not there to let him in.

Are there any lockboxes or hacks anybody has so that I can leave my key and he can get in my apartment? I’m hesitant to just leave the key under a mat.