Stock Price Charts

What is the rate of capital gains tax for retiree? My dad has been retired for several years now and has not filed a tax return for these years. He receives about $12000/year in social security benefits - this has been his income since he retired. The value of his stock portfolio was about $35,000. He recently cashed out $8000 to pay some bills and use for basic needs. Will the $8000 be taxed? How much? He's planning on cashing out another $12,000. Will he be taxed on this and how much? Besides his stock he has no other assets. For ten+ years he's had all his stock in manulife. In December 2007 to present he's diversified his portfolio however the value has held at about $35,000. Will this affect his capital gains tax? Thanks for the assistance.