Our 4 month old grandson has been breastfed exclusively. His mom, our daughter, needs to treat a UTI with antibiotics and will need to stop breastfeeding for a while. Baby has milk allergy, both siblings had milk allergy also, and hates the taste of milk free formula...vomits after feeding and now refuses. They live in Croatia. I wonder if there is a homemade formula using other protein source, etc. that mom can prepare at home to feed baby without causing strain on kidneys or cause other allergies. Please advise. Thank you.