Hi. I am assuming your father is 82 years old and sleep problems are common as age advances. But the other complaints you mentioned point to a possibly larger issue.
Next Steps
Consult a neurologist/psychiatrist as soon as possible.
Till then, let him be accompanied by someone at all times if possible. Take him out but with someone by his side.
Health Tips
Do not challenge or dismiss his beliefs however impossible they may sound. Reassure him that you are there for him and his worries can be sorted out.