According to the information you provided, the amount of red envelopes given by a young aunt and her brother-in-law in the countryside of Nanyang City, Henan Province may be different due to different geographical and personal economic conditions. Generally speaking, on this occasion, brother-in-law can send 1000 yuan or 800 yuan's red envelope to show his blessing and respect. However, the specific amount also needs to consider local customs and personal economic conditions. If economic conditions permit, a red envelope of 1000 yuan may be more suitable; If the economic conditions are average, 800 yuan's red envelopes can also express blessings and respect. In short, the ceremony is light and the meaning is heavy. The key lies in the desire for blessing and respect.