Not just 20,000 but 40,000 British pounds in one month. Think of that money. I have friends that barely live a comfortable life, one of them only earns 400 British pounds a month, and here we see 40,000 British pounds squandered by gambling in one month. Now if that isn't utter stupidity - I'm sorry I have to say it. The person knows that 40,000 pounds is a big amount and he should have thought about it many many times over before deciding to give it away to the gamblers due to bad play.
The lack of self-control hit him or maybe the lack of guidance as well from the family but I say the latter isn't that common for young adults of this age. Sometimes it can't be avoided if addiction comes to play and those addicts only realized when something they've treasure most was gone to them.