For Federal parks, Being disabled he may qualify for a free Discount card.. How much the discount is depends on where and why you are using it, I will give some examples.
Access to national parks and forests: It may be as high as 100% off.
Parking in federal campgrounds, Forest service and COE, it may get you half off
Parking in concessionaire operated campgrounds such as Grand Canyon.
Gets you in the park free but no discount on camping.
COE parks (Which I mentioned above) Some discount, some do not, call ahead or visit reservation.gov. (By the way I am a senior, currently parked in a COE park for half price). There are over 2,000 discounts per the web site.
