I was watching the little boy grip the shower knob and I have to keep telling him to make a strong grip in order to fully open it. He still keeps asking for help to open it sometimes as they need to take a shower before the start of his swimming lessons under Red Cross and again after the class before going home.
I was looking into this triangle pointer knobs which offer strong grip feature but they are more for industrial use and not for residential and commercial use. But they are good for those that need a strong grip. I showed it to the little boy and he just smiled at me. Whatever that means he still needs to learn to give the shower knob a good grip to open it.