Where does it end?
You know what really annoys me? When people start quoting from religious books to say that God has made Man to be higher than animals - forgetting that it said in the first place that it said that animals were to be treated well! This is the latest missive from the daughter-in-law who is quoting scripture to say that people are more important than animals.
I read an interesting commentary that said that while this might be true (and of course this depends on what religion you belong to), the main thing is that the basic tenet underlying this is that animals are to be treated well to begin with. Many people forget that.
Anyway, the daughter-in-law has said she will stop writing to me because she will take it up with further authorities if she needs to. She is steadfastly silent on whether she has tried to speak with her mother-in-law. She has ignored my suggestions for mediation.
Her argument is thus - her son is ill, and his immunity is weak. Therefore her mother in law must stop feeding. I can see the chain of logic from one to two - however I don't see how it links to feeding the cats. I have suggested that the mother-in-law be asked to shower and change her clothes before coming into contact with any of them as an additional precaution, but she did not respond to that either.
Here's the thing, if everyone who has an argument with a family member decides to go to the authorities, then when will it end? I can see that in some situations, where the situation is really bad, that the authorities might have to be called in, especially if someone is violent or abusive. In this case, this is an elderly lady - and what can the authorities to do make her cease and desist from feeding? What if in the future you don't like the way your mother-in-law hangs the laundry out, can you call your town council? Or what if your daughter-in-law doesn't spend as much time with your grandchild as you think she should? Again, let's involve the authorities!
If anything, counselling might be a good solution as Vegancat suggested, but she has ignored that suggestion too.