You cannot actually claim these expenses as your own deductions against your own income.
You would actually have to file a return for your son since he is the one who would eventually be receiving the income from this "business" activity. But since your son did not actually have any income for the year, then he really has nothing to apply these deductions against. However, these can all be considered start up costs for his business for if and when he does start receiving income from this business venture. When that happens, you may claim start up costs from prior years at that time on a return which you will file to report any income he earns.
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Thank you JA