My son is a year old. He is not taking any kind of solids and denying everything even after trying so hard. Thus, I am giving him tonned milk. Earlier I was giving him cow milk, both causing him constipation. I asked paediatric and she advised me to switch to tonned milk but it's also not working. when I gave him cow milk mixing water, it did not cause any constipation. what should I do as the doctor has said not to mix water