My father is about to turn 70 and he's employed. He has the option to continue working but it's unclear to either of us if he'll be able to collect social security while he has his job?
He will be able to collect the full amount. From the Social Security website, emphasis added:
If you were born January 2, 1943, through January 1, 1955, , then your full retirement age for retirement insurance benefits is 66. If you work, and are full retirement age or older, you may keep all of your benefits, no matter how much you earn. If you’re younger than full retirement age, there is a limit to how much you can earn and still receive full Social Security benefits. If you’re younger than full retirement age during all of 2015, we must deduct $1 from your benefits for each $2 you earn above $15,720. If you reach full retirement age during 2015, we must deduct $1 from your benefits for each $3 you earn above $41,880 until the month you reach full retirement age.