Lately I reached the stage, where I think, DS has left his old life behind and will try another one far away. That he said to his wife not only one time, he can't take it anymore, sounds like advance warning. At least in his mind was it working already, IMO. He searched perhaps for a way out, but quitting his dream job (??) wasn't an option. Being on the road without breaks, the family at home without him, nevertheless always money worries (IMO, he MUST have had) - maybe, it was no longer conceivable to continue for the next 20 years (his pension very late or even never at the horizon).
Maybe, his $$ left in his truck were meant for possible damage, for example to the loaded piglets. So he wasn't stealing, he wasn't causing material damage for his last client, but "only" left his family. Maybe, when the family of his wife was visiting, it wasn't a reason for hindrance, but showed him even more, how very well his wife would manage the family without help. She herself said so in the beginning after DS' disappearing, that she had lived as a single mother before DS and didn't need a husband.
IF he disappeared on his own, Idk, how he would be able to return one day in the future. At the time, when he first ran away, he had no family and certainly much less debts. Now his way back will be rather impossible, IMO.