Tonsillar Lymphoma Stage 3 or 4

Hello,
This has been such a long process. Over a year since my husband found the tumor on his tonsil. He's been diagnosed with tonsillar lymphoma, mixed cellularity, stage 3 - possibly 4. They did a bone marrow biopsy and found 5% blast? Not sure what that means. He needs another one because they didn't get the other sample they were hoping for. They used 17 viles of lidocaine (they ran out). So he has to have that again plus they are putting some sort of shunt in his chest to administer 8 cycles of chemo. I wish I had more exact information but he is very "to himself" about what the doctor tells him. I'm frustrated... I want to know EVERYTHING!! If they find more in his bone, then it will be stage 4. This is his second time with HL. The first time was in 1997 - diagnosed with IIIB. Can anyone shed some light on this for me? He also has presence of a tumor in his stomach. Keeps getting worse. I hate not knowing what's next as far as what to expect. We weren't married when he had it the first time. I also need to know how to explain this to my kids who are 14, 8 and 6. Exhausted...this is so consuming for me as well. I feel so helpless.