DD214 if the gate-opener. Then it comes down to combat vs no combat zone duty and income/asset level. The VA has a website and there is a link at the bottom of this page about veteran's benefits.
Call your local VA dept. Set up an appt with their rep. Take all your Dads records. If he served during a war, he may be able to get Aids and Attendance.
https://www.agingcare.com/veterans-assistance