It is impossible to know what Paul's life would have been like had he survived, but one of the crucial points made in the book is that the lives of the young men had been altered in irreparable ways by the conflict. As Paul observes in Chapter 5:
We were eighteen and had begun to love life and the world; and we had to shoot it to pieces. The first bomb, the first explosion, burst in our hearts. We are cut off from activity, from striving, from progress. We believe in such things no longer, we believe in the war.
Clearly, boys like Paul would struggle to pick up the pieces and get back to normal after the war. It is also obvious that a massive gulf has developed between Paul and his home, where people don't seem to understand what he has been through. With his education interrupted, many of his friends dead (many of the young men in his unit were from his class in school) and his mind tormented by the horrors of what he had seen, we can predict that life would have been difficult for Paul after the war.