You're still just treating the symptoms instead of boosting his immunity, which will prevent the colds & ear infections from starting.
Medicines have been researched and approved - and then there are problems and the FDA pulls them. So yes, you are right to be concerned. Still, you're only treating the symptoms.
I would use nutritional supplementation for prevention - that's what we do. A friend has 3 daughters, 2 with asthma (one of whom had to be hospitalized with every attack) and one with ear infections (tubes recommended). She used nutrition and no one needed tubes and all are off their inhalers & nebulizers. But no pills, and no gummy vitamins! They don't work.