朋友（绿卡）的姐姐（已退休）和姐夫准备来美旅游，请教问题是：
1，她的姐姐申请资料时是否要填写她妹妹家的资料？
-Yes. It is important to tell the truth and this will not affect her visa application.
是否就像其他普通旅游一样只填他们的资料就可？
2，让妹妹写邀请信请他们来比较好？
-Up to her. If they will come with the tourist group, may not need the sister's invitation. Otherwise, it is helpful to have the invitaton letter.
好像资料要求比较多，较麻烦。
谢谢
