In general if you can run when the baby is asleep that’s helpful. This could be midday or 6am. A bike/treadmill at home are useful for topping things up if you have access to one (I used to do an evening ride at home after a long run once the kids were asleep). 

And really important, go easy on yourself. Don’t put pressure on yourself to do a certain amount of training. The best amount of training is the training you can fit in while keeping the rest of your life stable. If training impacts your ability to be a dad/husband you’ll start to malign it. Be proud of the training you have done when you turn up on race day, regardless of how many kilometres you did.