It is common to want to be sensitive when your loved one is doing something not quite right, but it is always beneficial to tell them. Do it with some kindness. For example, don’t say, “Mother, you are doing this all wrong—do it this way!”
Instead, try, “Mom, let me give you a hand. What are friends for?”
It doesn’t usually work to instruct or teach, since they may not understand or be able to remember the information.