How Can Hair Growth And Weight Be Regained After An Illness?

My daughter s 8 year old , last year in january she suffered from a disease , whatever she was eating was vomitted out in 5-10 minutes , after long medical cure doctor suggeted Flourocent Barium test ( something like that) and they found whatever sh was eating it was bouncing back and not going down through food pipe ( i dont exactly know the terms for these Sorry for that) LAter sh was given some medication Syrups to take and she recoved . this whole diagonostocs took 5 months and she lost lot of her hair and weight.Please suggest how can she regain her hair growth and weight .