I applaud you for wanting to jump into the deep end of quilting a big quilt for your friend. However, since this is your very first one, I recommend you think smaller. A sofa quilt. Something that he could take a nap under (or any of his family, but made with his height and wingspan in mind) . Make it comfortably long and wide. Believe me, that will mean a lot to him and he will use it often. Besides, it's more than brave of you to start with a sofa quilt size.
Keep in mind as you peruse pictures, the more pieces it has, the longer it will take. Think bigger pieces, less cutting and sewing. Best wishes!