How to stop recurring reflux for my 7 month old grandson? He has had it since he came out of hospital, he was prescribed gaviscon, but he still spews!

Reflux. Gastroesophageal reflux in infants is usually outgrown by year of age.If child growhing and not avoiding eating the problem is not serious.Again positioning erect, frequent rather than large feeding, burping frequently help. In one stance antiacid therapy, the above maneuvers do not help. If child vomits 2-4 hours after eating, this means stomach is slow in emptying. Need to evaluate stomach.
Sit upright. If he is a "happy spitter" as explained by dr. Juster, just make sure you sit him upright after every feeding for at least 10 minutes. Also you can stop in the middle of the feeding to burp him and to make sure he is not feeding too fast. You can even stop multiple times if needed. The good news is that most reflux is gone by age 1.
Ask his doctor. If he's a 'happy spitter' (i.e., has reflux but is growing well, eats well, and has no other issues), nothing else may be needed; 75-90% of kids outgrow their reflux by 9-12 months old. If this isn't the case, he needs to see his doctor to (1) ensure there's no underlying cause, and (2) see if he'd be a candidate for one of the anti-reflux medicines.