If the vet did not clarify something for you, it is your right to ask as many times as you need. I'd call the office and have the vet call you back with the info you require.
Enemas are good but giving this to a cat will make him tired, and yourself. Talk to the vet about soft canned pumpkin, which is a stoll softener, and see how you can make kitty eat it. It works if you can get him to eat it. You can even add some salmon oil to the pumpkin to add fish flavor, since cats usually love fish flavor. Also, Physillium Husk, in powder, added to the food can do wonders. It is a fiber product and it is safe to give it to the cats. When my cats get a little constipated I just add this and problem solved. Omega is primarily for skin and coat. My cats are given Omega every day yet they tend to get a bit constipated when I get lazy and don't give them physillium husk.
But.....you may want to call the vet first :)
I have a cat who gets constipated and I give him a little squirt on Omega 3 oil in his food every night. The product is made specifically for cats and is good for the coat of the animal too. Believe me I understand because this cat who is ten years old started vomitting and the vet cost for xrays and treatment was over $700. And all she did was find out he was constipated and gave him castor oil, Good luck. PS I would worry that he is not drinking and eating. Make sure he is not getting dehydrated by checking the skin at his neck if you pull up on it and it stays up "tents" he could need IV fluids. You could try giving him chicken broth (boil the chicken and save the broth) or tuna juice to encourage drinking. Also, chicken is easy to digest so giving him boiled chicken or even meat baby food (make sure there is no onion powder in it) might tempt him.