Most kids outgrow it by 6 months; others with really bad cases can take up to a year or more to outgrow, but it does get better after 6 months usually. 9-10 months is a normal growth spurt for kids and a normal sleep disturbance period (like the "4 month
wakeful"). It could be a natural part of his age group more than the GERD. But with GERD, you don't want to make sudden changes to diet ...