Welcome to OCF!
Please do not misinterpret the 5 year survival rate as meaning he will only be here for 5 more years. That simply means that at 5 years post treatment the survival rate is only about 55-60% of everyone who was treated will still be alive. That shows you oral cancer is nothing to play around with! Ive seen patients with terminal diagnosis survive for several years while others who seemed to have a much less invasive case of OC pass away. There is no rhyme or reason, (to be blunt and repeat what one of our long time members would say)... you will either make it or you wont.
I suggest going to a major comprehensive cancer center (CCC) and seeking the best medical care you can for your brother. Below is a list of CCC's. They are the countries top hospitals to treat cancer and where your brother should get the most up to date treatment available. The CCC facilities all use a team based approach where the specialists get together so everyone is on the same page. If you cant get to a CCC, there is also a list of the top US hospitals. Look for a teaching hospital or university hospital. Find the best medical care you can and get a second opinion.
CCC List US News Best Hospitals List You have found a great place to get info and support! We will help both you and your brother get thru this so stick with us.