Braiding has nothing to do with age, but with the length and quality of hairstyle. So in theory, a 40-year-old can also wear two braids. But braided hair needs to be wound into a spiral shape, and it needs a long hair to arrange, otherwise the braid will appear loose and weak.
For the elderly, hair becomes more sparse, soft and easily broken, which may affect the effect and durability of braiding. So before braiding, you need to consider whether your hair quality and quantity are appropriate. In addition, it takes some skills and time to compile and distribute. If he has no experience or time, he may need to ask others for help.