You do not report your dependent's income on your tax return.
If your dependent made more than $6300 on a W-2, or had self employment income of more than $400, he/she would have to file his/her own tax return.
If the only income for dependent is social security benefits - no need to file at ell.
If he/she is required to file (as I explained above), please be sure that the dependent indicates on his/her tax return that he/she is being claimed by someone else.