Thank you for your query.
The description provided by you is suggestive of an increasing lesion in the brain which can explain:
1. The initial headaches
2. Change in behaviour.
3. Urinary incontinence
There can be bowel incontinence but you mention that your son is having diarrhoea
which needs to be investigated.
As the full detail of the MRI
finding is not present it is very difficult to suggest any further solution. It is advisable to repeat a MRI and follow the neurologist's guidance.
I hope I have answered your query to your satisfaction.
Wishing your son an early recovery.
Rajiv K Khandelwal