Hi Tia, sorry you haven't had more responses here, I understand how worried you must be about your son.
I have Lymphoma, and while long term enlarged lymph nodes are a symptom, so are drenching night sweats, appetite loss and significant weight loss. I lost 8kg this year.
I think if your son is otherwise well (i.e.: eating, normal weight and no night sweats) that's a good sign.
Good luck.
S