Wow, that’s just rude!
I think you should definitely bring it up but in a nice way. I don’t get people like that who just have no regard for anyone else.

Sounds horrible. Hopefully you can start the conversation

I think gently start the conversation if you feel comfortable. How you’ve come across in this question shows you’re quite reasonable and well mannered about it. You can even be honest and say you’re a bit uncomfortable/embarrassed/whatever bringing it up but that you’re finding the car noise a bit much through the night, is there anything he can do.
Are they renting or do they own the property? If own, you want to think long term that this is someone you may have to deal with for years to come so approach with the long goal of being neighbours in mind. If you get no luck from a polite request, you could try reaching out to your council regarding the technical noise level to see how they can support the issue. If it’s over a certain level there may be things you can do.

This is a hard one. I think you’re going to have to try very politely to bring it up with them and not let it escalate into an argument. All you can do is ask. I hope it goes well.

That is so horrible! I wish you the best of luck.

Aw I can understand this is very annoying. I would probably first look what I could do myself. Improve insulation in your house, close doors and windows, buy good earplugs

Oh you poor thing. I guess it depends on how your relationship is with the neighbour. If you are on good terms you could mention it but the reality of it is if he has older cars then they do need to idle a little before driving off. This is not required with newer cars. Its a tough one because if you mention anything and you dont really get on it could just make matters worse.