Just this weekend, my dad gambled $50 on Friday, $100 more on Saturday, and $300 on Sunday (this $300 consisted of $100 he had brought and another $200 he got from a cash advance). He's used roughly a grand in the past two weeks, and despite my family's best efforts, will not consider treatment.
A bit of history about this problem, he's been gambling for the last two years, beginning with trips with business friends. However, he began going alone later on and kept using larger and larger amounts. Eventually this reached a peak when he spent $1300 in one night through a huge string of cash advances. This night he returned to the house a gibbering mess, and threatened suicide several times. Though I was able to talk him down from this state and see him agree to get treatment, this never happened. He attempted to quit on his own and failed.
Since those three weeks, he spent continually larger sums until he reached this weekend, another breaking point. The problem is, he is actively refusing help. He admits that he has an issue that is hurting the whole family, but is unwilling to join a support group or get counseling. He once again believes that he can quit on his own, that we should give him another chance.
Now, onto my situation in this little conflict. I'm currently a college student with a reasonably steady job. I live at home during the summer, but am financially independent otherwise (pay my own tuition, have more than enough surplus for my expenses, etc). I fear that part of the reason my dad did not quit successfully the first time was because I had to go back to college; I was only home for a weekend. I also fear that he's hurting my mother and sister quite a bit and I'd like to somehow get them out of this situation.
What can I do to help him past this problem?
EDIT: His game of choice is video poker, if that makes a difference.