A skeleton horse can be tamed by killing the skeleton that is riding the horse. Then, the player will be able to tame it. A saddle is required, too.
You can summon a skeleton horse whenever you want using a cheat (game command) in Minecraft. There are many options for summoning skeleton horses. You can spawn one that is wild, tame or wearing a saddle. A skeleton horse does not spawn naturally in the game so you have to use the /summon command to spawn one.
Provide high quality alfalfa or grass roughage with a complementing grain to balance the horse’s diet. Feed by weight, not by volume. Always maintain at least half of the ration as roughage, such as hay or grass. Never feed moldy or dusty hay, grass or grain.