Keep it simple. I've found that an excellent admonition for celebrating the holidays with an aging parent.
To capture the "good old times" your parent may remember, try one or more of these simplified traditions.
If your parent enjoyed attending the Nutcracker, the Messiah or other live musical performances, listen to CDs or DVD's of these favorites together.
If your parent hosted family and friends during the holidays, give him or her a guest book and a tin of cookies or other treats for guests.
If she sang in a church choir, hold a carol sing-along, even if there are only a few of you.
If he faithfully chopped down and decorated the family Christmas tree, take a drive through a lighted neighborhood, stopping for cocoa afterward.
If she filled your Christmas stockings to the max, provide some wrapped candies she can give to the grandchildren and great-grandchildren.
If she baked traditional breads and holiday cookies, hold a family baking session, using her recipes and encouraging her to help if possible.
Can you think of other simplified versions of holiday favorite traditions?