Concerned my close girlfriend is dysfunctional and self destructive

I have a very close girlfriend, one of my best girlfriends, who makes really bad relationship decisions. I can’t point fingers too much due to my own past mistakes, but she’s having a new guy move in with her after only technically 3 dates. They spent two full weekends together and had one dinner date. She claims she’s never felt this way before, blah blah blah, and is head over heels "in love" already.

But what I hear her doing instead is inflating how long they’ve known each other, exaggerating his intelligence level, and inflating her own feelings. They knew each other in high school 30 years ago, but she claims she’s known him for 30 years. They only just reacquainted themselves recently.

She also claims he’s “brilliant” yet she hardly knows him. He's a property manager for a high school for his career. That doesn’t take brilliance. Sorry, no offense, but how is he brilliant exactly??

She's 50 years old and has a stable career, earning over 200k in salary and owns two homes, renting out one of them. He’s 49 years old, living with his parents, he wants to change careers and go back to school. He's not even certain of which field he wants to pursue, she tells me. My gut reaction says he's looking for an escape from his parents home and for a sugar mama to take care of him financially while he goes back to school.

How convenient for him. He wants to go to school so he found himself a desperate, financially well-off woman willing to take him into her home. I don’t trust the situation at all, given that he wants to move in so fast.

A few other red flags have popped up that she's also dismissing, even though she acknowledged the red flags to me and said they're concerning. The very next day, she acted like we didn't even talk about it and she moved onto discussing details of him moving in with her, right after also telling me she was going to take a break from him for a couple of weekends. That idea went right out the window, and she moved onto discussing him moving in instead.

I am worried that my friend is a bit crazy and unstable, and that is concerning to me. This is not the first time I’ve seen her make stupid moves in love. Two years ago, she almost married a highly unstable severe alcoholic, when she was aware that he drank far too much. She almost moved to Portugal to marry him and live in Portugal with him, giving up her homes, her job, and her whole life. One of her last boyfriends she ended up completely taking care of in every way, who needed a mother and a crash pad, not an equal partner. She seems to take on men who are serious projects and who need help.

I think she may be codependent. I used to be codependent myself, so again, I am not pointing fingers, but I think we are just in very different stages of growth.

I told her she’s being very unhealthy about this, rushing in so fast and committing so soon. I was upfront with her about how I feel and gave it to her straight.

But I know she won’t listen to me. She is super headstrong on this and has already decided he can move in with her. I told her she’s being very foolish. I also told her that I think she’ll end up supporting him financially.

I’m aggravated by the whole thing. I can’t stay close to her right now. I’m going to have to back off, and I told her this. It’s too hard for me to watch my close gf make such a stupid mistake.

I'm in such a different place in my life, and I can’t deal with unhealthy, ungrounded people, and I think she's acting very ungrounded and unhealthy. It appears to me like she's so desperate for a relationship that she is willing to do anything to have one.

Where I am in life is so vastly different! I'm learning from my past mistakes in love. I've outgrown being codependent and I am leaning on myself to live and be happy on my own. I'm being very picky and judicious about men and who I get involved with. My energy, time, my home, my finances and my mental health, are so very precious to me.

And honestly, I am now beginning to wonder if my girlfriend is unbalanced. It sure seems that way right now.

I only want and need healthy-minded friends around me at this stage in my life. That's the direction I'm moving in and healthy people are the kind I want to be around.

So, my question is, how do you create boundaries and distance yourself from an unhealthy situation while also remaining good friends with her? How do I support her, but from a distance?

We also live many states apart, so we don't physically see other. We text and talk on the phone.

Thanks for any advice you can give.