Tell your husband. He probably won't enjoy hearing this news, but it would be strange-and probably weigh heavily on you-to keep it a secret from him. And openness with your spouse is more important than secret-keeping for your mother-in-law. Then let him decide whether to tell his dad. He'll have to consider all the usual things, like whether your father-in-law is likely to accept the information or explain it away and whether this is the right moment, given his delicate health.
I began doing restoration exercises about four months ago. I love it. My glans is already more sensitive and the skin expansion/growth is boosting my soft-size, which is a nice little confidence builder.