We have a Blue Badge for our daughter, and as daffy says, its for the person, as is the car if you get it with the Mobility Allowance,
Parking,
With the Blue Badge, (no more Orange ones), you can park on single yellow lines, (but read the parking notices), If he gets a Motorbility car, (which we have),all the info he needs comes with it.
As for the Rail etc, go down to the Booking office and ask, there are some concessions, but they vary,
If there's anything else you'd like to know, just ask.