Thanks for your query
Your father need to undergo fasting and post-prandial blood sugar estimation because diabetes may lead to such symptomatology.
does not present with these symptoms.
These are the symptoms of peripheral neuropathy
and diabetes is a cause of it. So diabetes has to be excluded in this scenario.
Again thyroid problems especially hypothyroidism
may lead to such mood swings and constipation
. So i ask you to go for free thyroxin (FT4) and thyroid stimulating hormone
(TSH) assay to exclude thyroid problems.
Along with this complete hemogram should be done in order to exclude anemia.
Other investigations if at all needed should be guided by the results of these preliminary tests results.