Probably isn't it, but I found this on TvTrops.orghttp://tvtropes.org/pmwiki/pmwiki.php/Main/CrashCourseLanding
"This has never happened in a big jumbo jet, but there was an early 1980s episode of That's Incredible where they tell the story of a husband-and-wife who went up in his small plane. During the flight, he has a heart attack and falls unconscious. The wife, getting instructions from the aircraft control tower, successfully landed the plane. "
Though, the time frame fits at least and with 30-40 yr old memories a tv show could easily be confused for a TV movie. Who knows there might even have been a tv movie of the week done based on the incident. Perhaps the child with lukemia could have been another part of the same episode. Can't seem to find an episode list. No luck there on either IMDB or TV.com
Here's the wiki link FWIW.http://en.wikipedia.org/wiki/That%27s_Incredible