If the Alaska Permanent Fund Dividend is the only unearned income he has, he is not required to file a tax return and so you do not have to include the income on your tax return either.
The amount of the 2016 Permanent Fund Dividend is $1,022.00.
Your child is required to file a tax return for 2016 if he had only unearned income (interest, dividends, capital gains) of more than $1,050, earned income of $6200 or more, or a combination if he had both earned and unearned income.