Story time: So my mom's computer has been being flaky. It is very old.

In response to this, my high school boyfriend, out of nowhere, decides to buy her a new chromebook

Ships it to her overnight through Amazon

This shit is crazy. But now my mom is being really ungrateful and I feel like an asshole

Ex-BF also called his siblings in Florida to arrange one of them to set up the laptop and show her how to use it.

Mom is like: old laptop is back working now so I'm going to leave this one in the box. Tell him not to send people over I don't feel like dealing with it now. Maybe in a few weeks or something.

I suspect she is considering how to get money out of it instead of the laptop.

That would be very, very in-character for her.