Simple answer: Yes, you can use the entire capital loss carry forward against this year's capital gains.
But taxes aren't simple. Technically, you should complete mock returns for those others years, to calculate the actual amount of carry forward. You are allowed to use you standard or itemized deductions to reduce your taxable income before having to use your capital loss. But, you have to use your capital loss before you use your exemptions amounts. If your only income was Social Security, your taxable income is zero, so it's pretty certain that the entire amount carried forward. I wouldn't bother to do the calculations, unless you hear from the IRS (unlikely).
If the home was your primary residence, you are allowed a capital gain exclusion of $250,000 ($500,000 Married filing jointly). You must have owned and lived in the home for at least 2 of the 5 years prior to sale.
