1999 F150 Engine eating oil

My dad has a 1999 F150, with a 4.6l . He told me that ever since it was brand new, the engine has always burned alot of oil, at an abnormal rate. He said he would always find himself adding oil to his engine to keep it at the normal level. Up until recently, he doesn’t drive his truck nearly as much as he does, and he usually brings his vehicles to get the oil changes, on this most recent occurrence, they said they had to add 7 quarts of oil to it...Now to me, that is just insane. How come this engine likes its oil so much? He said he wish he had brought it back to the dealer, but he said he never had the time to be without his truck, and unfortunately now that it has 105,000 miles on it, it’s obviously way too late. What your take guys, how come a brand new engine up until 105,000miles would be eating oil so much?

my 97 with a 4.6 did the exact same thing, before it was time for its wvery 3000 mile oil change I would have to add 3 quarts just to make it to 3000 miles and it did get worst as time went on, when I traded it in it had 195000 miles on it, It didnt leak a drop of oil and it didnt smoke so the only thing that I could figure is it was getting a constant extremely small supply of oil from somewhere to the cylinders to burn, not enough to make it smoke but just enough to show a loss of oil?