My Granson Is Very Colicy; Born 12/11 My Daughter Is

my granson is very colicy; born 12/11 My daughter is breastfeeding; lots of milk every 2 hours round the clock; has taken him in to pediatrican every 2 days it seems, Her 1st son was on previcad at 3weeks until age 2. One of Dr prescribe Zantac I think 3 drops 2x day Its been week no relief. He propels milk and screams for 1 1/2 hrs every feeding We are very experienced my other daughter had colic for 6 months! We walk and use over the arm method to rock and walk him My daughter is off all dairy and meat and is hardly eating what else can you suggest I WILL PUT MY DAUGHTERS EMAIL BELOW