Welcome and thanks for posting your query to HCM.
It appears from your problem that your nephew has "Atopic Dermatitis".
Atopic dermatitis is a type of eczema
in infants and children manifesting as reddish bumps over skin particularly over cheeks, elbow and legs.
It generally starts by the age of 3-5 months and then progresses with remissions in between. It exacerbates whenever there is change in weather or extreme environmental conditions.
For the betterment the persons taking care of baby must take special efforts to prevent the aggravation of the situation. The baby must wear all cotton clothes, completely covered. Staying away from hot and humid environment. Trimming of baby's nail regularly.
You need to meet a dermatologist
and have proper counseling and then further guidance for long term regarding this condition.
Hope these informations are helpful.
"Wish you good health"
Dr Sanjay Kumar Kanodia
MD (Dermatology & STDs)