I think since your sister's boyfriend's father gave you a red envelope when you got married, it is natural for your sister to get married in return, and your parents can arrange the worldly wisdom in money, but now that you are married and have a small family, you will naturally start to learn the worldly wisdom between friends and relatives, so you should give red envelopes to your young couple and buy some small gifts as a blessing. Tip: When my boyfriend and my sister got married, my boyfriend gave me money. I gave him a golden passepartout. It was not very expensive, but it looked cheerful and pleasing for your reference.