Managing finances properly is key to our financial life, which is well known to each of us, I guess. I feel like this is in my bones so sometimes I make some decisions subconsciously. I recently ran into a situation where I found myself really awkward. Last July or August(I can't remember that clearly), one of my extended family cousin asked me for three thousand dollars as he lost his job and could not pay off his loans. I refuse to lend him the money cause I knew him well that he was not a solid trustworthy guy. A few days ago we met on a family reunion occasion and he did not really talk to me and I suddenly realized that it was because I didn't lend him money last year. I think about it twice and if he had not been that untrustworthy, I would have definitely lent him the money. Anyway, I hope he is doing fine now and best wishes to him.
The dilemma you are facing is not an easy one, and almost every person on the planet faces it. Almost all of us have relatives of some sort. There are few solutions here: either lend money to your unreliable cousin, forever forgetting about this money (because he will never give it back) and then you will maintain your family ties (but is this so, because you will no longer treat your cousin as before); or - don't give him anything, as you did and ruin your relationship with him. As you can see, in both cases, there will always be someone dissatisfied with this state of affairs.
Money at any time can spoil the relationship between people and it doesn’t matter if they are strangers, friends or relatives. This could have been avoided if people had fulfilled their obligations to each other. They borrow money, and then don't return it, and they are still offended by you. Completely forgetting and confusing that this is a request, not a requirement.