Just as a side observation, I'm really interested in the way judgement about addiction and substance use is bound up in this language about fiscal irresponsibility. "He’s been spending all his money on drugs since then....I feel terrible for sending him money that he’s almost certainly going to blow on drugs" kind of thing, where the cousin is making threats to family members but the LW's remorse is phrased as if the problem is wasting money.

Also, sometimes knowing that your spouse would not want to send money to a relative in trouble is a good reason to do it without telling them, within whatever limits are reasonable in your relationship for discretionary spending. Like, if I was inclined to help someone by giving them money and my spouse would be upset about it, that's a conflict of our values and potentially an issue of compatibility in our partnership, but I don't think it impacts whether I should send the person money that I have discretion over.