Most everyone in the cattle business takes care of their cattle, there are a few that for what ever reason don't.
Most of us understand that they don't need to be rolling fat to be healthy and depending on time of year, weather conditions etc their can be quite a range of body conditions and still be in good health.
I recently bought some thin cows that I had the intention of feeding up to better shape, I've done that off and on for years.
Currently have an 11 year old registered cow that has bad feet it's been an issue her whole life but early on didn't cause any problems, with age it's gotten more pronounced and she has progressed to where it's hard to get around in winter. She stayed in decent shape last year but this year has not so we have her and her calf in a lot where she is close to food and water. She is gaining some weight back and plan is to sell her soon.
We may have something newly purchased or old that looks less than good but we try to improve them or get rid of them. Most of us understand there is no money in undernourished cattle.
Where the problem comes in is generally with new comers like the subject of the OP that don't really understand the whole range of things that can happen like more experienced cattle people do.
That said we are often thrown for a loop by things but we, I think I speak for most of us when I say we try to stay on top of things fast and try to stop a potential problem before it goes very far. A new person will not always understand the subtle clues to illness, or may not realize certain nutritional needs.
There are now lots of do gooders out there that see something they think shouldn't be. We live in a state road with about a mile road frontage.
Fairly common event for a passer by to come up the drive and tell us a cow is calving, once somebody said a cow was stuck in the pond.
We always go check out whatever they say, sometimes it's helpful, other times it's a false alarm. We always thank the the people and tell them we'll check on it.
It does get kind of frustrating because we live in an area where if cattle get out we're the first place people think of that the cattle are from, so we get a lot of that. We have and do sometimes have something get out, like everybody else, but more often than not it's somebody else's. We have some young new neighbors that have been having cattle out. They are trying and will learn but it takes some time and learning from experience. We've helped them and are willing to continue to help them.
A few years ago we had a bad situation where some other neighbors were put in prison for drugs and their cattle and horses were getting hungry in the middle of a bad winter. Both us and another neighbor were having those cattle get in on us. We found out then what was going on and in the process found out that both the local animal shelter nor the sheriff department had any jurisdiction over the matter and kept putting the issue back to the other. The sheriffs dept did look into it and said that the folks had a family member coming from another state in the weekend to take care of the cattle. That apparently was enough to satisfy, but we wondered about the animals getting water during the extensive cold weather that was at the time and it wasn't addressing the fact that the cattle were getting out onto our and the neighbors property regularly logically due to being hungry and thirsty.
There is a fine line between getting involved or meddling.
If another landowner is being affected by the management or lack there of then it's a valid concern. There is a fine line between being concerned about a situation and addressing it vs meddling.
Reality is though that a bad situation can become your business if a nearby situation is being managed poorly.
In the case of the op, I believe
@Dave has valid concerns about the new neighbor, and it certainly looks like other folks in the area are going to have issues with the new neighbor over water. That person is likely to find out in a hurry that he is going to have to work with other people over the water usage. When somebody comes in to an area knowing it all it can be problem for the folks around that have to deal with the new comer.