I had an abscess drained and a seton inserted in my fistula in December, and went home the next day because we caught it so early. It depends on how bad your husband's case is.
Abscesses aren't so bad. They're drained and left to heal. Fistulas are more complicated. EDIT: sailorluna explained what a fistula is better.
The surgery isn't that big, and shouldn't take too long. An incision is made for the fistula and a seton (a "drain") is usually inserted, though it's usually just a surgical string/tubing that's left in the area to keep the wound open so it can drain for an extended period of time. Otherwise, there's a chance that it will just get reinfected and cause another abscess. So it's good to have a seton while it's healing, and they can be removed later.
If he has a fistula, they will likely suggest maintenance medications like immunosuppressants (6mp, Imuran) or biologics (Humira, Remicade). These both really help fistulas heal, particularly the biologics, which I would recommend strongly and am on myself.
Fistulas are incredibly difficult to heal for people with IBD, and there's a low chance of them ever closing, but those medications increase that chance, and also help it stop draining. Within a month of being put on Humira, all drainage stopped for me -- and even less with another abscess I've unluckily had since.
If you have any questions, I'm happy to answer them! I've had a lot of experience with this, unfortunately.