RockTXAggie -
I hurt with you bro. Take walks by yourself in nature and cry out to God letting him know exactly how you feel and what you are thinking. Pray for her healing, but most importantly beg God to not let this cancer be wasted! Around September of last year my pastor's sister was diagnosed and this was her prayer request.
This gave me a new way to pray for my sister. Of course I also prayed for healing, hope, understanding and her kids. My sister died in November of last year. The night she passed I picked up her journal and it was filled with raw emotion, scripture, and her last entry was her good-bye to this world entry. In this entry was a call for everyone to consider the claims of Jesus and to take Him seriously. This entry was read at her funeral.
God answered the prayer to not let the cancer be wasted although He chose not to heal her in this life. Watching her in so much pain wasting away was the most difficult think I've seen in this life. However God is faithful and she cashed in on all of His promises. So much more of Romans 8 is a treasure of hope during this time. Here's just a taste...
9 However, you are not in the flesh but in the Spirit, if indeed the Spirit of God dwells in you. But if anyone does not have the Spirit of Christ, he does not belong to Him. 10 If Christ is in you, though the body is dead because of sin, yet the spirit is alive because of righteousness. 11 But if the Spirit of Him who raised Jesus from the dead dwells in you, He who raised Christ Jesus from the dead will also give life to your mortal bodies through His Spirit who dwells in you.
12 So then, brethren, we are under obligation, not to the flesh, to live according to the flesh 13 for if you are living according to the flesh, you must die; but if by the Spirit you are putting to death the deeds of the body, you will live. 14 For all who are being led by the Spirit of God, these are sons of God. 15 For you have not received a spirit of slavery leading to fear again, but you have received a spirit of adoption as sons by which we cry out, "Abba! Father!" 16 The Spirit Himself testifies with our spirit that we are children of God, 17 and if children, heirs also, heirs of God and fellow heirs with Christ, if indeed we suffer with Him so that we may also be glorified with Him.
18 For I consider that the sufferings of this present time are not worthy to be compared with the glory that is to be revealed to us. 19 For the anxious longing of the creation waits eagerly for the revealing of the sons of God. 20 For the creation was subjected to futility, not willingly, but because of Him who subjected it, in hope 21 that the creation itself also will be set free from its slavery to corruption into the freedom of the glory of the children of God. 22 For we know that the whole creation groans and suffers the pains of childbirth together until now. 23 And not only this, but also we ourselves, having the first fruits of the Spirit, even we ourselves groan within ourselves, waiting eagerly for our adoption as sons, the redemption of our body.