How do I [25M] tell my friend [25M] he's single because he is creepy to women?

I don't think he is creepy in a predatory way. But let's start at the beginning. I've been friends with Dan for 5 years, so from when we were both 20. He told me after a year or so that he has never had a girlfriend though he desperately wants one. I just gave him an awkward pep talk more or less. Afterwards he sometimes made comments that rubbed me the wrong way, namely always talking about 'we' and how 'we' are so single and so lonely and 'we' will eventually find someone etc until I said that I'm not even looking right now and that I have no problem with being single, after that he stopped these comments though.
I am now with my GF since 3 years. Dan is still single and doesn't seem to have dated anyone at all in those years. We never talked about this again though and I wasn't sure if he's actively looking or not. However, a week ago we were both at a party of a good friend of mine. Dan knows her too but had only met her a few times before. We stood around in a group for a while and talked about harmless stuff, such as my friend (who is from Brazil) mentioning certain foods she misses from home. The next morning I wake up to a facebook message from her about how weird Dan is, because he apparently sent her a bunch of messages at like 3 am saying if she was his girlfriend he would make her brazilian food 'better than she ever had' every day etc. and just spamming her with 'nice' but very cringy messages, including some total racial stereotypes, totally inappropriate considering he had just met her. She included screenshots btw so I know it's true.
At first I didn't know what to respond and wrote 'oof yeah he's a bit lonely sorry' and she told me Dan has somewhat of a reputation among girls because he basically hits on every single woman he meets way too soon and always in a super cringy way. Apparently at the party, when I was gone for a bit, he asked another random girl to 'go watch the stars outside' with him in front of everyone and then pouted when she said no and complained that women don't like romantic men anymore. I mean I know he can be a little bit socially awkward but I never thought he was THIS cringy to women. I really want to let him know that 1. he will probably stay single until he resolves this 2. he makes women genuinely uncomfortable. But I'm pretty sure that since this has always been his sore point he won't take it well. Any good ideas on what to say?
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**tl,dr:** My buddy Dan is always single and sad about it, but now I've learned it's probably just because he's so cringy and weird to women. How do I talk to him about it?


Source.