Parking on the lawn in every place I have ever lived is a code violation....They can call for that.
You are assuming all the cars belong to one person...Each car may have a driver n( kids, spouse, in-laws) that reside there.
You playing musical cars sounds like a you problem....Maybe you are the one who needs a wider driveway so you can park side by side.
There are normally 3 cars in my driveway and we park in a way that everybody can get in and out without have to play musical cars.
No he does not need a bigger property if he is parking cars legally on a public street. As long as they are registered, tagged and in running order, they can park on the street.
I worked for Public works years ago and if there is no alternate side parking the city/village will normally post the street with no parking in order for the street sweeper to be able to access the street for cleaning.
If it's a residential street that street garbage you refer to isn't going to happen. That is usually an issue on major thoroughfares and mixed-used areas.
If the people that live there don't clean up in front of their homes that is a bigger issue than on street parking.