Fludarabine, Busulfan, and Antilymphocyte Globulin Followed by Donor Stem Cell Transplant in Treating Older Patients With Hematological Cancer

RATIONALE: Giving low doses of chemotherapy before a donor stem cell transplant using stem cells that closely match the patient's stem cells, helps stop the growth of cancer cells. It also stops the patient's immune system from rejecting the donor's stem cells. The donated stem cells may replace the patient's immune cells and help destroy any remaining cancer cells (graft-versus-tumor effect). Sometimes the transplanted cells from a donor can make an immune response against the body's normal cells. Giving antilymphocyte globulin before transplant may stop this from happening. PURPOSE: This phase II trial is studying how well fludarabine, busulfan, and antilymphocyte globulin together with donor stem cell transplant works in treating older patients with hematological cancer.