I recommend combining funds even though she might have a really big, growing tantrum baby on her hands when she revokes his debit card, and relegates him to a weekly or monthly cash blow fund. She will at least know the bills are paid, food for the family, gas for automobiles etc is being covered. Gambling and their associated debts will have to be paid out of his blow money. You don’t have to say a word to dissuade his habits, especially a gambling one, it is a very cash conscious enterprise where debt is strongly discouraged.
Again, the hardest part will be the the temper tantrum and ill spirit he will display in an effort to wear you down, shake you down, extort more money… You have to be able to stand firm in this.