For a guy who has no chance, he's doing an annoyingly good impression of someone who might actually win...
The main piece of good news to hang on to if you'd rather not see Trump winning the presidency at least is that so far he's arguably been rather lucky in his opposition. Until recently, he merely had to stand out from a huge field of candidates, who either weren't worth taking seriously themselves (as winners, at least -- Rand Paul, Carly Fiorina, Ben Carson) or who were similar enough that they could split the "anti-Trump" moderate vote (Bush, Christie, Rubio, Kasich). Now the field has been squeezed from over a dozen candidates to just five, while Trump's support has remained pretty flat at 40% or so for a couple of months. It's an open question where Cruz and Rubio's supporters would turn if either pulled out -- but the point is that Trump's best work so far has been standing out from a pack, rather than against a single opponent. He might well be able to adjust to that too, of course. But his campaign style of bluster, bile, divisiveness and just generally behaving disrespectfully to any and all opposition is unlikely to appeal to the moderate voter.
It's no longer impossible, though. I had thought (or hoped) that Trump's support would start to fade once the voting actually began. That hasn't happened (except in Iowa, and even there he was a strong second). So yes, it is a possibility.