Hi and welcome.
First of all he needs to see a cardiologist to rule out cause of palpitations. He might need baseline tests like EKG and physical examination. Next he should see a psychologist who can help him fight his insomnia by different behavioral cognitive and sleep therapies and he needs to taper down lorazepam very gradually to avoid withdrawal symptoms. Moreover he needs to cut off alcohol and caffeine intake and make a set routine for sleep and wake cycles in dark quite room with minimum disturbances. Chamomile tea an hour before bed time and regular exercise and yoga can help a lot.
Let me know if you have further questions.
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Wish you good health.