Get some rest and love on your boy. It's so stressful when they don't feel well.
On the enema...We are home from the vet. He hasn't pooped yet from the enema but hopefully it'll be soon. He went straight to his box to pee and now he's finishing his breakfast. I really hope this clears up his remaining issues.
My only concern with the lactulose is that he generally has softish stools anyway. This is something we've been trying to manage through diet. I'm a little worried it might cause diarrhea, but I think for now it's more important to just get him back to normal. The instructions on it are twice a day for 5 days. I don't have the dosage in front of me at the moment. I wish I could talk to his normal vet before proceeding, but unfortunately they are closed until tomorrow so I think I have to just go with it today.