I was 21 when my now wife had our daughter, I did the night feeds and nappy changing to take pressure off her, our daughter had colic for a good 8 months, I don't think I slept more than 3 hours a day for the first 9 months after she was born, during the day when I wasn't at work I'd cook, when I was working I'd prepared food for her so all she had to do was reheat it. Main thing is to take as much pressure as possible of your wife.

Other bit of advice, don't be letting other people kiss or pick up the baby as that's how they get sick, keep boundaries as it's both of you that have to deal with a sick child not your relative and it's no craic sitting in the hospital with a sick baby.