Take it to a vet.
He is both a pet cat, because you can pet it, and a stray cat because you can stray it. :)
Only a vet will be able to prescribe the correct medicine for an ill cat. Never try and medicate a pet yourself as this could lead to overdose, and in extreme cases, death of the cat.
you will know that your pet is ill when it is acting strange rarely eating and does not have much energy
My bad, I meant: How should you pet your cat?
it depends on the cat
Yes, fleas can make a cat ill because the bites can get infected
if it gets it from another ill cat, or if it gets some sort of disease or illness
Feed it and pet it.
No, I have never had a pet cat that has been hit.
read a book about cat or pet or let them see cat sleep on your phones and a tv
It is an observation because you can see that the cat is ill so it is visual.
All who have owned a pet cat.