Neighbors left cats outside on long vacation

Neighbors left cats outside while on vacation how long should I wait to intervene

There are 2 cats thar started showing up on my porch about a month ago. They are supper friendly and very chatty. One has a collar and the other doesn't but they're related and the one without a collar has a mark where one used to be.

All of the neighbors notice that these cats are around alot and have been showing up all day but also late at night around 1am to 3am. We have figured out that they belong to our neighbors at the bottom of our street.

I was able to look at the house which looks like no one has been home for a while (trash cans left out, no cars, plants knocked over in the front and back). There is no cat door and instead there was a feeder that was filled with food. (There was a bunch of it so it's either bad and the cats don't want to eat it or someone has been coming but not very often). There was also a very small water bowl and some litter boxes. The part that I'm the most concerned about is the shelter. There was a cardboard box with towels in it. Nights are getting colder and days are getting hotter.

The thing that is weird to me is that the people that live in that house are very wealthy with expensive cars and furniture, so why couldn't they spend more than a cardboard box.

In my area cats are able to free roam and I have 2 cats that go outside but to have them outside all the time is not great. A neighbor called someone related to animals for the city and they said that they can't do anything for cats since they can find shelter. They can intervene with dogs though.

Some people suggested taking the cats to a vet and scan their microchips, however, the family that owns them is fairly new to the neighborhood and don't speak English so they probably won't be microchiped. The husband of the family is verbally abusive to the wife which makes me concerned that that might escalate and effects the cats.

I want to take them in but I'm afraid that they won't be able to be indoor cats since they're so used to outdoors and the neighbors will see them and take them back.

As of right now myself and other neighbors have been putting food and water out for them and I made a more secure and warm shelter under our deck while we decide what to do and possibly introduce them to our 2 older cats. Also I wouldn't take them to a shelter since I'm worried they would separate them since they're a bonded pair.