The VA period of war for Veteran's Pension purposes is August 5, 1964 - May 7, 1975. Your father being discharged in 1966 would appear to have the requisite service to be eligible to apply for the VA Veteran's Pension Program with Aid & Attendance. The veteran does not need to have served in combat overseas just needs to have served on active duty. I recommend that you contact a Veterans Service Officer in your area to assist with the paperwork. They will be able to complete all of the necessary paperwork and assist you through the whole process from start to finish. You can locate once near you through the VA's General Counsel Website OGC - Accreditation Search
. All of their assistance is at no cost to you. I caution anyone who is asking you to pay, gaurantees benefits or states that they can get it done faster. It's the VA they move at their own pace and I have only seen them expedite 3 claims in almost 4 years.