Is Dexolac Hi Kal Stage 2 Safe For Infant, And Which Formula Should Be Used For Weight Gain Given Her Vomiting, Diarrhea, And Low Weight?

Hi sir, my brother s daughter is 7 months baby we are using dexolac hi kal stage . previous doctors suggested to use dexolac hi kal up to 6months .now we are using dexolac hi kal stage 2 without concern doctors . Now my brother s daughter getting motion and vomting can please suggest me which type of power to use for weight gain now baby is 6.5months 4.6kgs weight