Can people still get the addictive nature through friendly games
It depends, as far as I know someone who already has an addictive nature, just as they are addicted, whether it's to drugs, gambling or other things, most of those who have an addictive nature don't care what friendship is, they keep making small or big gambling bets, it is very likely that they will do the same thing outside, not only at your place, other places also behave the same way, they can't if they don't carry out gambling activities, they have to do it every day.
So am just curious to know if these little games are the one's that got to him or already developed such habit and to know if possible that the practice will continue elsewhere after leaving there when he loses the money and to look for means through gambling to recover it.
Yes, they will continue gambling, they can't stop.
Addiction is a cultivated behavior that grows as the person keeps engaging in the action or activity. People become addicted to alcohol by taking a sip from a friend's glass and from that level they graduate to taking some bottles of beer or wine. Gambling can start with any kind of sport or activity. Some of my friends went into gambling from friendly competition like who wins a car race in video games to who wins a football match. When monetary benefits are added to some entertainment activities between friends and it could lead to gambling addiction if it becomes a steady adventure.