Hi.
Thanks for your query.
Noted the history about your Father and understood your concerns.
Since your Father is 81 years old, the aging can have its problems and comes under the purview of Geriatric problems.
Since the sensorineural function get delayed, it is possible that he has a momentary stroke that caused him
dizziness, shakiness and glazed overlook in eyes as the full and large meal does divert the blood supply to the gastrointestinal system.
But since he is loosing weight and had blood
diarrhea I would advise you the following:
Get a CT scan of the abdomen including that of
prostate and blood tests for all the tumor markers like PSA, Alfa fetoproteins VEA so that a chance of cancer can be ruled out.
ALso go for
psychological evaluation as senile
psychosis can be another reason for such symptoms.
Change over to another supplements as Ensure is not helping.
Ask him his likes and dislikes for the foods and beverages so that a proper nutrition can be maintained; this is the most important thing one looks over and misses out on this particular point.