Husband had surgery to remove anaplastic astrocytoma in oct. Finishes radiation therapy next week. Just started getting cold sweats. Is this normal?

Possible/ talk to MD. Taking steroids? Usually patients are on some dose of steroids this far along the treatments. The blood sugar levels can get ultered while on steroids. Monitor that and if it is ok, want to make sure there is no infections etc. If all is well, taking good dose of tylenol (acetaminophen) before bedtime usually helps.
Narcotic withdrawal? Another thought: if your husband was taking narcotic pain meds after surgery, and he is taking less, he may have cold sweats from withdrawal. This is very under-recognized and can be miserable for the patient. Other symptoms include yawning, eye tearing, feeling hot and cold, diarrhea, and feeling restless. If he has those symptoms, ask your doc about this possibility.
No. Radiation itself does not cause cold sweats. Most patients are on steroids and chemo and may have lower immune response. This could be viral or another type of infection. See your doctor for white bood count, temperature and describe any respiratory or urinary complaints.