Hi Amy! I am so sorry to hear what you and your dad are going through. Cancer is truly evil, and from what I've learned over the course of my adulthood, having a mother who battled both breast and oral cancer, OC can be extremely aggressive.
I just joined last night as I was seeking help and support myself. My mom passed away last week from oral cancer. Her diagnosis was only last August. After surgery and treatment we thought (hoped) she was in the clear, but only 6 weeks after her last treatment we found a lump on her rib and knew it was back, or as someone else said, had never really been gone in the first place. My mom's spread everywhere, so quickly, her bones, lungs, and liver, and who knows where else that we didn't see on the scan. She would have tried any treatment given the opportunity but the doctors didn't think she would be able to withstand more chemo being so frail already.
I am happy to hear your dads doctors are giving him options and a chance to fight this beast. It is the scariest most heartwrenching thing anyone can experience... for both patient and caregiver... and I can honestly say it has changed my life. I too am trying to find a way to cope with all of this, so you have a buddy right here if you want to do this together!
I'll be praying for you and your dad and sending you all the healing and positive thoughts in the world. Stay strong for him and absolutely spend every moment you can with him. I ended up taking a leave of absence from work for my moms last two weeks and it is the single best decision I have ever made. Make sure you say all the things you have ever wanted to say to eachother because if/when treatment works, you will value your relationship on an incredibly deep level. And god forbid the treatments don't work, you will have no regrets, only memories of a great love and respect for the man who helped give you life.