Jackie, this is indeed a tough one.
I'm not sure that God want's you to stop praying for your relative; rather I think has answered you in ways you did not expect.
We know that Jesus said the following:
Jhn 15:7
If ye abide in me, and my words abide in you, ye shall ask what ye will, and it shall be done unto you. But Jesus also said:
Jhn 14:6
Jesus saith unto him, I am the way, the truth, and the life: no man cometh unto the Father, but by me. When such situations as yours touch us we must realize that it is not God's plan for our wishes no matter how well founded they are. Rather we must let go of our anxiety and learn instead to trust God with all of our heart. We must put our faith in God that all is going according to his plan.
Of this Jesus spoke the following:
Mar 11:22
And Jesus answering saith unto them, Have faith in God. So in closing, I would not stop praying for your relative that she might find God; however, I would always add: "if it is your will for this to happen." or something similiar. I know what you are going through, well at least a little, for I lost a brother of mine in a similar way. He took his life and God's will was done. Perhaps I did not pray enough?
I do not hold myself to blame; we tried everything but he went down the road of destruction, just as God had always planned. All we could do was love him just as we are commanded.
I hope this helps a little Jackie
It's a pretty sad subject, but God IS in control
Love in Christ,
Darren