In order to be able to claim a dependent you have to fulfill these requirements:
1. The child must be your son, daughter, stepchild, foster child,
brother, sister, half brother, half sister, stepbrother, stepsister,
or a descendant of any of them.
2. The child must be (a) under age 19 at the end of the year and
younger than you (or your spouse, if filing jointly), (b) under age
24 at the end of the year, a student, and younger than you (or
your spouse, if filing jointly), or (c) any age if permanently and
totally disabled.
3. The child must have lived with you for more than half of the
year. 4. The child must not have provided more than half of his or her
own support for the year.
5. The child must not be filing a joint return for the year (unless
that return is filed only to get a refund of income tax withheld or
estimated tax paid).
If the child meets the rules to be a qualifying child of more than one
person, only one person can actually treat the child as a qualifying
child. See Qualifying Child of More Than One Person, later, to find
out which person is the person entitled to claim the child as a
qualifying child.
It appears that you can claim your son as a dependent.
