Above everything else, that cat needs to get neutered NOW!
Each year, approximately 860,000 shelter cats are euthanized. That doesn’t even include the kittens that die before they even get to a shelter. And so many do.
I feel terrible for their cat, but I feel more terrible for the hundreds of offspring he could create. Little kittens that never have a chance, not to mention the mom’s that are basically raped by the non neutered roaming males. And have pregnancy after pregnancy.
Theoretically, a female cat can give birth to three litters of kittens per year, with an average of four kittens per litter, in an average lifetime of 10 years ,this could result in up to 120 kittens in her lifetime. Then when her kittens have kittens the number becomes horrendous.
It is beyond irresponsible for your friend to own a cat. It would be better off rehomed if nothing is going to change in this situation.