I don't think I repled because I don't know. I honestly have no idea and I'm not sure who to ask. Whoever you ask, they have to be objective, knowledgeable and assume the prerequisite that we will have an RE crash. If you find out - or if anyone else here can enlighten us, I would like to know the answer.
Yield: Those are safe investments as far as principal, if held to maturity. Interest rate risk would be a problem if your mom needed to cash out. The Mae family is not actually government backed. Doubtful that the government would let the Mae's fail.
"The prospectuses for all of Fannie Mae's debt offerings clearly state that the U.S. government does not back the company's debt instruments. In fact, commercial banks, including the three that make up half of the FM Policy Focus board of directors, have many close ties to the government."