One problem with cat bites is that they are narrow deep wounds, and tend
to close up early, leaving infectious material inside.

I've found that keeping the wound open by soaking in hot water several
times a day and pressing out any fluid will help the body overcome the
infection quite rapidly, as shown by decreasing redness, swelling and
pain over a period of a few days without the use of antibiotics.

I'm not a doctor or a PA, but your friend might find this helpful in
addition to the antibiotics.  The body mounts a reaction to the
infection immediately which continues for a while even after the
infection is controlled, and antibiotics don't have an instant effect.

Note: cats seldom bite with real force unless they panic, but some cats
panic more readily than others.  Consider the circumstances of thsi
incident and try to figure out what caused it.  If you touch a tender
spot on a sick or injured cat, it may bite in reaction, even if it's tame.
If you do something the cat really doesn't like, it may panic if you don't
stop.  Cats are very strong when they panic.  If you need to do something
like get a pill into a cat or put drops in its eyes, get the vet to teach
you how.  It's important to be very firm and get it over with as fast as
possible.  People tend to be hesitant to hurt the cat, the struggling
and cries are effective in deterring them, and the repeated false tries
get the cat more and more upset.

Working with feral cats, or cats that don't trust people, without being
injured may require protective clothing, and substantial skill.

If the cat is tame, but just gets too excited when playing, you have to
train it to be more gentle.  You can try "talking to it in its own
language".  Kittens will cry when their littermates play too roughly
and mother cats will hiss at their kittens.  Crying like a kitten or
hissing like a cat may send the right signal.  You should also stop
playing immediately and put the cat down.  They learn pretty rapidly
by this regime.  It also helps not to let the cat get too excited
when playing with your hands.  Use toys so it can get as excited as it
likes without injuring you.

I hope this helps.