Hello dear, welcome to the medhelp forum. I can well understand what you are going through due to your son’s accident and behavior post surgically. I am concerned about the recurrent swelling in his temple at the site of the halo vest. You need to consult the neurosurgeon who operated upon your son’s neck. This could be a subdural abscess pressing on the meninges. Blood tests like cell counts, C reactive protein, blood cultures to track an infection, and assessment of the CSF. Cerebral MRI would be needed to check for any intracranial bleed post operatively or abscess causing these behavioral disturbances. Treatment would depend on the diagnosis and surgeon’s discretion. Usually parenteral antibiotics would be required if this is infective.
My suggestion would be to approach your neurosurgeon immediately. You are most welcome should you want any further clarification. Take care and all the best.
His recent abnormal behavior could indeed be related to the periodic swelling that happens at the old halo site. In order to rule this out, hopefully you can get him in to see a neurologist as soon as possible. Could be he's had an ongoing infection there. A scan should be ordered of his brain, to see what it looks like, too. These things take up a lot of time, unfortunately, I hope you can perhaps speak to your own doctor about the situation, so he can try to speed things up for you.
There is also a chance that somehow his lifestyle has changed, ranging anywhere from not getting enough sleep, not eating right, giving in to experimenting with various drugs, or maybe a blow to the head that didn't seem too important to him at the time. This is the advantage to talking to your own doc about all this, so when he sees your son, he will know the sorts of things to inquire about, he can give him a general checkup before he sends him along to the neuro, he can draw blood and see what's going there, and he can also talk to him about stressors he is experiencing at school.
Try to go ahead and set some of this stuff up, including a referral to a neuro, as well as your own doc might could go ahead and set up a brain scan, too, so the neuro might have it in advance of seeing him (which would be a miracle to time that out right!), and in this manner, when your son comes home for the Christmas break, he can see the two docs and get a scan while he's in your care. And while it could be it's a simple explanation why he's acting pretty wild, brain infection/injury and drug problems are very serious, so you must jump all over this.