How to deal with a toxic girlfriend

Woah momma. Ok first of all if he doesn’t see an issue with bashing you there is a problem. Definitely talk to a therapist about that I know a lot of teens act out but he’s not a child any more which brings me to my next point… why is he at your home still? He’s
Over 18, why in the world does he have a bmw and credit cards??? I hope the bmw is older than him. I’m sure you pay his phone bill as well, take that phone away! Set rules and stay firm. Your son needs a job to occupy his time, good luck!!

Thanks to everyone for the tough love. I agree this is about my son. He has chosen to go astray for what ever reason. I did not mention he is an identical twin which does not change the behavior, but just makes it more unbelievable to me. All my kids have been great kids. I’ve never had major issues with any. Sure, I have made mistakes, we are all human. It is just so shocking in a 6-8 month span the person we have known for 30 try’s is gone.
I had already taken his cell phone, credit cards, etc., from him as well as banned and trespassed the girlfriend. I failed to mention that. His father gave him an ultimatum, however, he lies and manipulates. His father does not have another house but works in the oil fields and lives out of a hotel far 6.5 hours from his school. His work location changes as the job moves forward. So, this is not a solution.
I agree he can’t live here. Campus housing is more than tuition and must be paid up front in its entirety. He has no friends do roommates are out. I actually considered a homeless shelter. Perhaps a hostel as a solution.
With that said I have installed cameras, etc turning my home into a SMART house to keep an eye on things when I am away which is 3 days per week.
I have considered dis-enrolling him from school and telling him if and when he gets it together we can discuss returning.
I have scheduled myself separately from my son with my daughters therapist. My daughters bi-polar manifested very quickly and many of the things he is doing are very similar to her prior to treatment. If and it’s a big if he does have a undiagnosed issue I feel my final piece of accountability as a mom is to ensure he is mentally ok. If not, I will help him. If he is fine and has just become a down right ugly perdón inside that is a different story. I do believe I owe him this much as his mother. Had I not lived through this with my daughter I may have. It even considered it a possibility.
In any event, he needs some sort of help and tough love I agree. We are a very close family and the whole situation is just outright shocking.
I would agree I was working far too much while the twins were growing up. Therefore, their dad left his job to stay home with them and provided a great role model. They have never been left to their own devices until recently upon starting college. They lived in the dorms last year. I made the change because the difference in debt due to the dorm in 4 years would be 100,000 vs 32,000.
He still gets good grades, attends class and studies. They have slipped a bit from a 3.2 to a 3.0, but are still acceptable.
I heard all of you believe me tough love and responsibility. My husband said he is weak minded. IDK and ties it really matter?
Our initial agreement is no girlfriend anywhere near our house. 2nd therapy is required. Otherwise he must leave. Perhaps I should have a firmer fist. I just can’t help but feel there is something else mentally manifesting. Throwing a kid…I know he’s 20 out on the streets and at least not attempting to determine if this is the case I just can’t to.
If it turns out he is just disrespectful and being ugly for no more than that is who he has become he has to leave. We all deserve our lives back to some normalcy.
Again, thank for the tough love and wish me luck.