My 4 years old son is saying weird things?

it all started as soon as he was able to speak but lately it became frequent, he keeps saying he is a guy from the past, he gave me full name and also started to draw himself as a guy in a suit, he told me he used to be married and he named the wife and the kids they had, my husband isn't taking it seriously but I think it is way too detailed to just be a joke
My 4 years old son is saying weird things?
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