Hello. I'd like to help you with your question.
At your son's age, he is too young to be expressing these types of thoughts and feelings. Because of this, it is possible that your son might be modeling behavior he has seen somewhere, either from his father or somewhere else.
Because your son's role model is his father and there is some difficulty there with the alcohol use, your son may be reacting to what he sees in the only way he understands at this point in his development.
I highly recommend that you have your son seen asap by his doctor and a referral made to a psychologist for an evaluation. Although your son could just be repeating what he has heard, any type of threats to harm himself or others should be taken very seriously and evaluated by a professional to rule out any psychological causes.
All my best to you,
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