This is a strong proof that if someone is madly addicted in gambling, he can do extreme and desperate measures just to satisfy his gambling addiction. Bad habits are hard to break. It takes time and strong mental stamina in order to break free from the usual routine you are used to doing. If the grandfather is excessively dependent on gambling, he'll definitely crave it to the point he'll do whatever it takes just to gamble again.
It's just so disappointing how a relative can be so selfish to put someone's life at stake for the sake of money. This is why we need to check up on the people we love to see whether they are doing just fine or they are going through some hardships such as gambling addiction which is a serious problem that needs intervention. By doing that, we could avoid things to escalate to this.
People kill to satisfy their addiction, he only kidnapped and got punished. I am trying to deduce his understanding of the word grand daughter. According to my understanding he doesn't care about anything else but his gambling addiction. He didn't even bother to foresee what kind of a crime he is going to commit nither its repercussions. The addiction has crippled his mind so much that he hatched the plan of kidnapping his own grand daughter.
If he would have in his young prime then he would have sold his kids and his wife for gambling. Why he did not do it might be because he was earning money at that time. Now at an age of 65 he couldn't work anymore but still needed money to satisfy his addiction and that might be the only reason he committed this henious crime. Good he was caught and put behind bars. For the rest of his life he would be haunted with this crime in his dream. He would cry and ask for forgiveness but he won't get that till he dies.