That's a great looking Free Spirit! It HAS to be restored in honor of your Grandfather! Whatever you do, don't get rid of it!
Looking closely at it, it kind of reminds me of my dad's (hardly ridden at all) late 70's Free Spirit. Back then, he and my mom bought his 'n hers Free Spirit bikes right from Sears. They rode them once or twice - if that - and that was it. Both bikes sat in the back of the garage for years. I had already moved on as the youngest/baby of the family and had joined the US Coast Guard in the late 70's right out of high school. Whatever happened to the old Free Spirits, is anybody's guess.