It depends- if you only have social security income, you do not have to file tax returns. If you have other income, part of your social security may be taxable. You can enter in TurboTax and it will calculate for you.
You can include your son as a dependent on a tax return if he is eligible to be claimed as a dependent
Social Security Retirement/Disability/Survivors benefits are reported on a form SSA-1099 and the benefits received are to be entered on a federal tax return. The benefits may be taxable depending on the amount of other income you have entered on your tax return.
However, if the Social Security benefits are the Only income to be reported on the tax return, then there is no reason or need to file a tax return.
To enter Social Security benefits reported on form SSA-1099
Click on Federal Taxes (Personal using Home and Business)
Click on Wages and Income (Personal Income using Home and Business)
Click on I'll choose what I work on (if shown)
Scroll down to Retirement Plans and Social Security
On Social Security (SSA-1099, RRB-1099), click the start or update button
Or enter ssa-1099 in the Search box located in the upper right of the program screen. Click on Jump to ssa-1099