Alzheimer should be ruled out first. Many times mild depression and anxiety disorder predominates. Once diagnosed properly then anxiolytic, mood elevator medication with cognitive behaviour therapy will help him to overcome his problem. Once he is taking his medication with doctor's advice then it is not habit forming . If he self medicates then it is problematic.

Your father can go for Psychotherapy / Counselling along with homeopathic medicines,  homeopathic medicines don't have side effects. The allopathic medicines, which he is taking is addictive. So homeopathic medicines firstly can be taken with allopathic medicines, asking the doctor. Slowly, Counselling/ Psychotherapy and homeopathic medicines will give the support to leave allopathic medicine with Doctor and Counsellor/ Psychologists suggestions

Hi... Did doctor (Psychiatrist) gave you any diagnosis? Is it Depression or Generalized Anxious Disorder (GAD)? Medication is prescribed by a Psychiatrist, so it's not wise to stop taking them without his consultation. Usually, it takes time for our body/brain to adapt to any medication and when it gets adapted to one, and if we suddenly stop taking it, it may produce some withdrawal symptoms. I suggest you strictly follow your Psychiatrists advice on this matter. Also, he will require regular Counselling Sessions from a Psychologist, especially if the root of his concerns are more psycho-social. If the root is more biological, medication will play a bigger role but Counselling/Psychotherapy is also equally necessary.