There are many topics that deal with weak/depressed family members.

I'll do my best to sum it up though.
Their health goes down when they are sick and once they are cured, it will naturally raise but it takes some time. You should continue giving them the fruit, vitamins, hand gel etc to encourage their health.
Making them go to bed or take a nap does not necessarily restore their energy. You can get them energy drinks if you do want to raise it with the game open, otherwise you need to let them rest undisturbed when it is late at night. When you open the game while it is late in the game, their energy will significantly lower.
Best of luck with your families!