Thanks for your query,
as you said your son is having 1 to 2 motions per day,he is active,afebrile so you need not to worry,and there is no need of giving lactose free milk.Take care of his hydration give him oral rehydration solution sip by sip after each loose stools,also give coconut water,curd, mashed banana,mashed potato,YOu should also give lactobacillus
sachet for 2 to 3 days,
avoid giving fruit juice.In case his symptoms continue take doctors advise.
Your son will be fine.