Jonathan lost one of his children, a son, during the recent war. Despite this personal tragedy, he still feels himself to be incredibly lucky. He knows all too well that many people in this long and bitter conflict lost their entire families, so Jonathan is grateful that at least he still has a family to love and cherish.
It's never explicitly stated how Jonathan's son met his death, but one can imagine that it may have had something to do with the war. In any case, Jonathan is able to move on from this terrible tragedy to make a new life for himself and his surviving family members.
Unable to go back to his former job as a miner, Jonathan sets up a business, which very quickly becomes successful. Jonathan is in a much better position than most people in this war-torn country, which only serves to strengthen his already optimistic outlook on life. It's notable that even after he's robbed one night by a gang of thieves, Jonathan is able to move on with his life and continue looking forward to the future with hope and confidence.
It seems that there are few setbacks in life, whether it's the tragic loss of a son, or the theft of some money, that are capable of plunging Jonathan into despair.