Never good to hear we may be losing a V40 owner Pchende, but I can't help but think young families are buying mid size SUV's all around the world in there thousands for a reason.
Can only recommend you consider things like ease of access/entry for things like baby capsules & strollers where I suspect the XC60 is likely to be an improvement over the V40.
Judging by the pics on the Volvo website the 2 cars are very similar inside & out except for the size & ride height so you're going to feel right at home with the controls etc.
You are the only one who really knows if the deal they are offering makes financial sense for your family with the extra costs of the baby in mind.
Make sure you really look the car over carefully as I do wonder why they are cold calling owners & offering such a great deal...
Sounds like it may have been on the lot for a while without selling so you have to ask yourself why?
With the baby in mind I would suggest that you steer away from a blonde interior though!!
The expression "That aint gunna buff out" comes to mind considering what babies can produce from both ends
Been there... Cleaned that
Lastly... A big congrats on the new arrival!! Your world is going to be turned on it's head... Mostly in a good way though