Can i still claim my son as a dependant even though he worked for two or three months?

[NewGuy]

It depends...how old was he, how much money did he make, was he a full time student, did you provide more than half of his living expenses....

[22cefis22]

He is 30 he made 1381.59 he is not a student and yes I did pay for more than half

[22cefis22]

Does he still have to file

[NewGuy]

He does not have to file due the amount, but might want to file if:

From IRS Pub 501-
Who Should File
Even if you don't have to file, you should file a tax return if you can get money back. For example, you should file if one of the following applies.
    You had income tax withheld from your pay.
    You made estimated tax payments for the year or had any of your overpayment for last year applied to this year's estimated tax.
    You qualify for the earned income credit. See Pub. 596, Earned Income Credit (EIC), for more information.
    You qualify for the additional child tax credit. See the instructions for the tax form you file (Form 1040 or 1040A) for more information.
    You qualify for the refundable American opportunity education credit. See Form 8863, Education Credits.
    You qualify for the health coverage tax credit. For information on this credit, see Form 8885.
    You qualify for the credit for federal tax on fuels. See Form 4136, Credit for Federal Tax Paid on Fuels.

[NewGuy]

Yes, your son would still qualify as a qualifying relative since he made less than $4050 last year and you paid more than half of his support. 

https://www.irs.gov/publications/p501/ar02.html#en_US_2016_publink1000220968