It's not looking good. He has pancreatic cancer, and is not going to get better. Though he has had it since the spring probably, and people with that cancer normally die within 6 months. He has stunned doctors and beat the odds. He was admitted to a community hospice last week for 10-14 days to be monitored, and to give my grandma a break.
I asked my aunt about our potential trip in March (didn't book tickets yet), and she said not to get them. Too much could happen between now and then. I am now facing the fact that I will not get to see my grandfather before he passes away, and am preparing to make a last min. trip for his funeral when the time comes. I have a feeling it will be sooner rather than later, but we have no idea.
Thank you all for the good thoughts and vibes. It's really tough to turn my phone on after work, in the morning, etc. knowing there may be a call or message of bad news. I am all too familiar with this situation unfortunately. I am going to call him tonight though to say hi.