But you should at least give it the college try first, right?

Frankly, I don't have enough information to know if this is the case. It's certainly possible that this is a relationship well worth saving, and that the overall net benefit is worth the toxicity brought on by his insecurities. The fact that she can joke about it certainly might indicate that the relationship is a safe and comfortable space for both of them despite his controlling behavior.

It's also hypothetically possible that she is exacerbating his insecurities by being overly flirtatious (or even flat out cheating on him) with her friends. In which case he might want to end it, as being in that situation will only reinforce his insecurities in his next relationship. (Hell, it's possible he is cheating, and that guilty conscience is making him project his infidelities onto her.)

It's also possible that she is not even in a relationship, and posted this simply as a joke she thought was funny.

So all things considered, the information provided only gives me enough to confidently say that trolling toxicity is pretty funny.

As far as the "correct answer here" and the value of giving it "the old college try", that's more between her, the hypothetical him, and maybe a therapist, and their friends, and innumerable other factors I'm not really qualified to speak on.