Will do, son, but my reason for responding is to encourage you in the strongest possible terms to get another opinion... "too old for treatment", when she's just 65, and the disease is leukemia?? That's become one of the more treatable form of cancers, from my understanding... and if that poor woman has battled lung cancer and cardiac disease, she's obviously a fighter...
Something just doesn't sound right there, unless you left something out (like the disease being VERY advanced)...
I've lost my Mom, coincidentally to lung cancer (and to carry the coincidence even further, we lost her sister, my Aunt Bertie, to leukemia some years back), so my heart hurts for you... Mom was 67 when she passed...
The only advice I can offer you is twofold-- spend all the time you can with her in her remaining time on this planet, and draw your family close, to draw strength from them... you can get through this, and your Mom wants you to... if she's anything like my Mom was, she's probably more worried about her family than she is herself...