My Son Is 9 Years And Had HSP 6 Months

my son is 9 years and had HSP 6 months back, which has lead to weakness and mild malnutrirtion, he complains of cramps some times, activities are all ok; his ped dr had prescribed him calcimax, which i gave him for one month, kept a gap of one month and want to start again, but i thought of giving calceferol sachet, not yet asked his dr again, can i ? thx u