The military provided all room/board/tuition and also provided cadets with $8200 as total base pay since they started at the end of June.
If the child is age 19 or older and has gross income of $5,050 or more then you cannot claim them as a dependent on your tax return.
Yes, as long as you provided more than half of his support for the year. For more information, see the TurboTax Help Article:
Who can I claim as my dependent?
You can also use this IRS online tool to determine if your son qualifies as a dependent: Whom may I claim as a dependent?