I think the question you mentioned depends on the personality hobbies of your friend and your cousin. In general, it is not easy to use money as a reward.

First of all, friends in the true sense learn from each other and help each other. No matter whether they are suitable in life or study or work, they are all true friends. I think since we are friends, we can get to know each other a little. He helps you learn skills, so you can also help him in other places, especially its weaknesses and your strengths, so that you can learn from each other and have long-term communication at all levels. If you use money in return, maybe he will think that you are a money-oriented friend with a weak friendship.

Cousin's situation is not much worse. This situation is a kind of emotional debt, so it is often not advisable to measure this debt with money. On the contrary, it is only a friendship between friends and you, and it is a kinship between cousins and you.