A medic reduces crew death on any ship. They were very popular on CVs because until a patch a while ago planes being shot down could result in a veteran death. Now that planes being shot down won't result in vet death, medics are not worth it IMHO on any ship. A seaman will never be better at a job than the sailor meant for the job. I.E. an engy will be better for your engines than a seaman will. One thing I have noticed though, is that my 120 UK seaman adds about 350ish (if I remember correctly) soft defense. This is even with no other sailors on the ship. I think this is because seamen have rediculously large amounts of sailors and even though they don't have very high growth numbers, they have a huge true ability score. Also the number to the right is not their ability. I think you can see their ability when they level up.

In the recent event, I removed a medic from my Essex CV to add an extra FP.  Interestingly, the crew death of skilled sailors went up whereas before crew deaths were not that common.
No vets were killed.

When the medic was put back on the ship, the death of skilled sailors went down although rookies still tended to die.

I didn't keep count of before and after.  And, it could have been a random type of occurence, but in this instance, there was no doubt that without the medic, I had higher then normal crew deaths.

This event required participation in 100 battles and I did virtually all of them with a CV.