HI..thanks for writing.. i have understood your concern.. the late stages of alz. dementia is very difficult to take care... your mother in law must not be taking proper food and liquid orally..so it may be the cause for low blood pressure.. another important thing is salt restricted diet for hypertension..if she has hypertension then she must be given salt restricted diet, it may be the cause for low B.P. if I will be the treating doctor, the I would have gone for blood investigations like serum electrolytes..and complete blood count.. she requires proper intake of liquid as well as food..u have hospice coming is good..u shud call and give details of abnormalities u have found... but remember that the stage is late and u can not expect any significant improvement, now its just a palliative care left.. i hope u ll find this advice helpful..best luck..