Please get him fixed ASAP, even if she's fixed he'll attempt to mate with her which is painful and stressful. This shouldn't change his disposition, other than greatly reducing any desire he has to roam. It also would prevent pregnancy if any unforeseen situations come up where you have an...
Where did this kitten come from? Do you know if it had diarrhea before you got it? It's extremely worrying that these kittens are getting diarrhea almost immediately after entering your house -- I wouldn't take in any other kittens until I figured out what might be going on. You definitely want...
Ok, I would definitely switch to bottled water or pedialyte for dilution, and use a bleach-based cleaner on surfaces the kittens may have come into contact with. Deworming is recommended for all kittens starting at 4 weeks (or as young as two weeks), even if they don't have diarrhea. A broad...
I assume this was a stray cat and not actually "your" cat? It really would be best if the mom could be found, but it sounds like you're doing everything right with this baby so far. Dog milk would in theory be a good cat milk substitute, but practically there is the danger of disease...
Kittens can be dewormed at two weeks. Are you diluting the Royal Canin milk in tap water? It's possible that's contaminated; you may want to dilute a fresh batch in unflavored pedialyte instead. How quickly after receiving the kittens do they start showing symptoms or dying? I would not give...
It may be worth switching entirely to KMR. Other milks have half the fat, protein, and total energy provided by cat milk: protein is 75 g/L in cat milk vs 35 g/L in goat milk; fat is 85 g/L cat vs 38 g/L goat; energy is 1210 Kcal/L cat vs 690 Kcal/L goat; calcium is 1.8 g/L cat vs 1.3 g/L goat.
I think you should mention to your mother that spaying/neutering all your cats will be -- literally-- thousands of times cheaper than allowing them to keep having litters. If she can't afford to take a cat to the vet, how can she afford 5x more mouths to feed and litter to buy? What is her plan...
The first one is calico so definitely a girl, the second one also looks like a girl but I can't tell what the annotations are supposed to mean?, and third is kinda hard to make out.
A spay/abort will be much, much, much, much, much cheaper than allowing your cat to have kittens. I went through 50+ cans of wet food and a 40-lb bag of litter per week fostering just 4 7-week-old kittens, and then after adopting two of them almost immediately spent $1000 on their second rounds...