Should I just let my brother make the same mistakes?

My brother is a hopeless-romantic which explains why he's thousands in debt thanks to his ex. He is not your average hopeless romantic, he is the kind that will devote all his time and money cutting off friends, family, & putting only her first. Of course now he has a new gf to tend to, although I love her and agree that she is very sweet. I"m watching him do it all over again. I'm worried because 1st he is my brother and 2nd his "obsession" has caused me financial loss before due to bailing him out of situations. Our dad is helping my brother pay some of his debt but has made it clear that he is embarred of his son's cowardly actions with women & yet that still doesn't refrain him from his old ways. He allows his gf to drive his uninsured car- who has a suspended license, & $1500 worth of tickets. Refers to the car that our parents bought him "their" car, so if I or anyone wanted to use the car he would consult with her first. Which brings me back to my question, Should I just let my brother make the same mistakes? Or should I keep intervening? I don't want that guilt-ridden feeling for not helping him if something bad were to happen but then again a lesson needs to be learned on his part. What should I do?