Hello. My husband has been lethargic on and off for
Detailed answer below.
Welcome to the 'Ask A Doctor service'.
I have reviewed your query and below is my advise.
Your husband could have some transient ischemic attack or some cardiac problem.
So for that 2D echocardiography and CT scan brain should be done for primary work up.
So kindly Check whether these investigations carried out by your cardiologist or not.
If all that comes normal than investigate with serum blood sugar estimation, serum TSH estimation, serum sodium and pottasium estimation and liver profile.
If he is having any severe depression or anxiety history than it can be causative if all reports comes normal.
According to my opinion you should consult him to neurologist for detailed evaluation and examination.
Hope I have answered your question.
I would be happy to help you if you have further questions.