These are not the typical neurological symptoms caused by lyme, the common symptoms would be short term memory loss, depression, anxiety, headaches. These symptoms could be MS, creutzfeldt Jakob disease or another neurological disease. The patient should see a neurologist(s), if he already did, get another opinion. Sometimes it takes several doctors to find out the problem
I am very sorry to hear about your wife's son.
Is it possible for him to see a new medical doctor (physician) in Poland or in the UK perhaps?
Given the serious nature of his condition, finding a new physician for an evaluation would seem to be a good step.
Whether this could be Lyme is difficult to say. Lyme has different symptoms in different people, as you may know, and seeing an experienced physician would be my suggestion.
Wishing your family the best --