Seeking God's Presence

My sister began chemotherapy yesterday. She will be treated with six, three-hour sessions of chemo given through a porta cath, one session about every 21 days. Afterwards, she will begin six weeks of radiation treatments on two tumors found on the left breast, and on the new 'hot spot' found through a scan of the area surrounding her right breast, a portion not removed by the masectomy. It seems harsh to have undergone the violence of a masectomy and then have spots show up on the breast tissue not removed, which could be cancerous.
My first reaction, not spoken to my sister, was she must have had an incompetent surgeon. But, on further reading of others' experiences, I am learning that cancer behaves this way. The surgeon isn't the culprit. Cancer is the enemy. While her body is pumped full of poison to kill cancer cells, I am seeking spiritual tools to combat our mutual enemy (cancer is only one of his weapons) through a book that teaches about prayer, "Prayer, Finding the Heart's True Home" by Richard J. Foster.
Perhaps 'combat' isn't the correct word for prayer. After spending time with God, I don't feel combative at all. I feel comforted. I came away from time spent with Him feeling that He is in control and that nothing happens to a child of God without it first being filtered through Him. Even cancer.
I found this statement by Thomas Merton, in the chapter about Contemplative prayer comforting: 'The message of hope the contemplative (prayer) offers you is not that you need to find your way through the jungle of language and problems that today surround (the task of seeking) God: but that....God loves you, is present in you, lives in you, dwells in you, calls you, saves you, and offers you an understanding and light which are nothing you ever found in books or heard in sermons.'
I need to feel His Real Presence. Thankfully, He said that when we 'seek him with our whole heart, he will be found.'