How do you fix your extremely weak family in virtual families?

Usually when one of your little people is weak, you can just give them a fruit such as a peach or banana from the shop. You can also try buying healthy foods and feeding your family and eventually their health and energy will go up. If they continue to stay weak, then buy the doctor's consultant (stethoscope from the shop) and place it on the character and it will come back with what type of medicine should be bought to cure the weakness.