Trip with terminally ill little sister

My sister amy was diagnosed with terminal cancer 7 months ago, this was devastating to us all especially her 7 year old son connor and partner lazer, recently lazer passed away very suddenly, its been so hard. Kiss fm recently had us in the studio and suprised amy and connor with a fully payed trip to the gold coast along with many other amazing things. My sister and i are very close and she wanted me to come with them to help out and to have great memories, with 6 kids money is very tight for me. and my sister amy who i am fundraising for payed my flights without telling me, this makes me feel terrible and i would like to repay her as she is in need herself. I feel terrible doing this but please if anybody can help it will be greatly appreciated xxxx