I wanted to add 2 things:
1) The only way to conclusively diagnose lymphoma is through a biopsy. Does your husband have any swollen lymph nodes? If so, his doctor should do a biopsy ASAP.
2) My best friend survived lymphoma, and has been perfectly healthy for about 5 years. There are 2 types, but both have high survival rates. So even if the worst comes true, keep your hopes high because many, many people live with and recover from lymphoma.
