If your friend has Jesus as her Lord and Savior, be happy for her. She is in the most wonderful place and I’m sure she sees Jesus on occasion. Not to mention family members that have gone on decades before (centuries?). Think of the family reunion. Wow, that’ll be huge.
I expect you will be sad at losing her presence for now, but as a Christian, you’ll see her again. Guaranteed. Her and many others you have known that have gone before you. No hurry to get there though. Heaven is not going away. It doesn’t have an expiration date. It’s God’s. There is no rent. He owns it.
As family, it’s part of our inheritance. And God is rich.
As a side benefit, the devil is nowhere around there. Righteousness required. And through Jesus, we are properly attired. To our heavenly Father we look good. Real good.
We may not know until we get to heaven why your friend’s condition went undetected. Perhaps she knew something and said nothing. We’ll have to wait to know. It likely will not even be relevant by the time we get there. Too much joy.
So, for now, just look forward to seeing her again someday. Best thing you can do for her now is to see to it that her family and friends know Jesus and will be there with her too someday. That’s the best thing you can do for her right now.
god bless you and keep you.