How much bleeding is normal from a surgery drainage site?

I called the local 24 hours nursing hotline and they're pretty useless, they ask questions for about 10 minutes then always say "well I can't tell you over the phone but go to a doctor if you're unsure."

My husband had a disc repair between L4 and L5 Thursday morning and for some reason the hospital sent him home yesterday morning. He was given some stuff to change the dressing and told to have it changed once a day.

Last night I changed it as it was freely bleeding out of the dressing and there was a blood pool on the back of his pants. The surgery incision doesn't look like it is bleeding but the drainage hole off to the side open and still freely bleeding. He was sent home in this condition.

Currently the dressing is bright red in an area about 2" x 2" but not pouring out yet.

The nurses didn't bother to talk to me about the dressing care although I'm the one taking care of it. Nor did they send written instructions. I really don't know how much bleeding is normal and when to be concerned. I don't want to run off to the hospital if this is actually normal. He's looped on oxycodon for pain and doesn't clearly remember what they said. I tried to call to the unit he was on and they say "call the surgeon", I called the surgeon who is not in his office today. Nursing hotline is no help. His discharge sheet says "call surgeon or return to hospital if there is drainage from incision" does that include bleeding from the drainage hole or just puss or plasma from the surgery site?

Please, if you know ANYTHING about this type of care please let me know. I have no experience of my own to draw upon for this.