Emaline, this sounds like a direct quote from the lives of my friends Jason and Lara. The thing is, Jason and Lara are not so cleanly separated and are sort of dating again (and again and again: they do break up a lot, but this most recent time was a huge deal and was like a Break Up). But Lara is
codependent. Basically this means that she desperately needs people to need her, and if she feels that she is becoming less necessary to the people she wants to need her, she will create problems for them so that they will need fixing by her. A lot of this is unconscious. In fact, until he dragged her to a Codependents Anonymous meeting, she didn't even realise it was unnatural, much less a psychological condition.
Lara does not have a job. In all the years that I have known her, she worked at Kroger as a cashier for like 2 months, when suddenly she somehow managed to pinch a nerve or slip a disc in her back and could no longer stand upright for that long anymore. I am not sure how she slipped a disc because she doesn't
do anything except fuck boys and cheat on her boyfriends, and I am not sure how she could have known that a pinched nerve is what happened because she makes a huge deal about not being able to afford health insurance, but either way, that is the story. Jason is marginally smarter about the money thing, it sounds like, because while he also went into debt buying her stuff, it was only stuff that they would both benefit from (food, rent when they were living together, sex toys, etc). That he and his credit are now suffering is his own fault, but he is well aware of this and considers it worthwhile.
Anyway, Lara is clingy. Lara is passive-aggressive and jealous and entitled. When Jason was out with other girls while they were more definitely broken up, she was constantly interrupting him with phone calls and texts, the same way your boyfriend's friend is. Jason realised later that he should have told her to fuck off, because ultimately it ended up costing him a potential girlfriend(s) (I will save what a tragedy I think this was for another day) who did not want to deal with that. However, he had to lose the girl he was interested in before he discovered that babying Lara and indulging her bullshit whingy tantrums and letting her pull him aside to Talk whenever they were out in public at the same place were all bad ideas; it took all that for him to learn.
So maybe it is the same with your boyfriend: it may take something a little more serious to knock some sense into his head. I am not saying you should leave him (unless you want to), but every boy I have ever known has some curious and incongruous blind spots regarding particular aspects of girl-relations. And this is not the sort of treating-girls-as-another-species thing, just occasional events where they deal with it funny. This may well be one of those.
Sorry I don't have any advice to offer, and if you weren't looking for perspective or empathy, well, that is all I got.