More details needed

Detailed Answer:
dear,
Welcome to HCM
from your information I can understand is that you are suffering from fronto Temporal dementia, have lost 25 lbs weight and you are concerned about low appetite.
well, fronto temporal demetia is characterised by personality changes and psychiatric problems, therefore we need to consider depression, psychosis, psychiatric conditions,etc as a cause of low appetite.
secondly, demetia can have motor difficulties that can interfere with eating process, which needs to be considered.

I would want to know..
1) if you feel depressed, low , sleep is disturbed, loss of interest in pleasurable activities, etc.
2) are you being suspicious towards people for no apparent reason, hearing of voices like complaints in absence of sound source, etc

I would suggest you to provide information about the behavioural problems and associated other complaints here if present.
further elaboration on your complaints can help.
we need to consider other cause such as malignancies esp at this age.

considering all this I would suggest a psychiatrist consultation will help.

we shall continue to discuss, kindly followup with the information.

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