you. to lay there and say, you have one leg, how am i going to live the rest of my life? >> you did right. i question god as to why. >> why me? what did i do wrong and why did my life change this way? but i've learned to get over that in terms of, it happened, and i had two choices -- either continue to learn how to walk or to give up, and i'm not a person who gives up easily. >> reporter: no. none of them are. bill did learn to walk. and son kevin, he's running the boston marathon. you still feel the shrapnel at all? >> i do. it doesn't hurt. >> reporter: kevin explains why this is so important to him in his blog. the name of your blog is "footsteps." >> yeah. for us, the concept of footsteps was taking steps forward from where we were. and with my dad, that's literally walking. so, those are his footsteps