Advice please re teen DS meeting up with a girl he met online

[selfcare]

DS (16) has just informed me he is going to meet up with a 17 year old girl from another city tomorrow. She will be travelling to our city. He says he met her online. He is not streetwise at all. He has a diagnosis of ASD and rarely leaves our house. He says he has spoken to her on the phone so he knows it is definitely a teenage girl. Please can you advise of any safety tips I could share with him/put in place? I am pleased he's putting himself out of his comfort zone but also nervous about him being in town with a complete stranger. Thanks in advance for any helpful suggestions.

Oh God. We also have this issue with our ASD DS. It’s a nightmare! So far we have always managed to arrange it so one of us gives DS a lift so have actually seen who he’s meeting.
We also know his iCloud password so we track him by using find my phone so we know where about she is.
It doesn’t stop us worrying though.
He’s on his 3rd ‘girlfriend’ met this way. Why can’t they just meet them in person rather than hooking up with randoms on the internet?!

Is being in the town at the same time an option? Can you track his phone? No clue what else to suggest unless you say for him to invite her to your house -although then surely her parents would worry?

Track his phone, stay in public places, don't go off somewhere private no matter how nice she is. If he's taking the bus have the ticket in his pocket or something just in case his wallet goes missing... chances are it will be fine though

Thank you for the helpful responses. I will be in work so won't be able to hang around nearby. In some ways I don't want to - I want him to have his freedom and opportunities to develop independence. Just feels a bit scary I guess!