A Medic is an original unit from the game, The Conquerors. The unit is lesser used, due to users either not caring due to a large army, armor, money production or it could be replaced by a Hospital.
These units are sometimes used in the Survival gamemode, as an army, due to certain allies not going out of the capture point (circle) to get their units healed.
Mostly used in the middle of the game, they are used to heal soldiers, tanks, and more while in a war. People also use them in early game if they do not want to do damage to a power plant or nuclear plant nearby an energy crystal. The healing of medics stack with one another. The healing of medics & hospitals is single-target! It is not an Area of Effect heal!
The healing of medics & hospitals are the same.
Since a medic soldier cannot damage any other unit, they are useful in big battles far away from a barracks, or tank factories. You should put the medic in the middle of the soldiers to be protected in case a tank or an army of soldiers are nearby. Another use is to put the medic away from the attacking army and having the army retreat when low on health, be warned using this strategy, as a powerful attack can kill the medic quickly.