Feeling my Dad has Advanced cancer.

My Dad has an ulcer under his tongue so after 2weeks his GP sent him to see a consultant at hospital within a week & told us it was not an ulcer but cancer & that my Dad has had it a long time not just 2 weeks & it was under his teeth & in his jaw as well, he said it was big (over 3cm I think)  he is waiting for a biopsy, cat scan & he already had a full blood test on the day,my Dad didn't ere all of it.Consultant said it would take 4 weeks & if I had any questions  but I couldn't think at the time. My Dad was 76 on the 14.04.15  & his appointment was the same day.He in as lost weight because he's not eating as he's in a lot of pain plus having difficulty chewing & some times he is finding it hard to talk, he is now on stronger painkillers & morphine as well, he has toothache & ear ache as well as not having any energy in him as that's not him. I know there will be no treatment for him as not in good health plus they would of got him tested by now. I am only just holding it together as I'm with him every day so it's going to be so hard when we find out it is & knowing I will lose him one day, just don't know how to cope with it.