Hey there, if he has reflux, then his discomfort needs to be address before you do any sleep training. If he's in pain, he'll wake up. You know, you'll just putting in lots of effort for no gain. So, once you're happy his reflux is properly controlled with meds, and he's eating well, he'll be in a better position to sleep.
If he's waking up, but not crying, then I would leave him to it. Listen to what he 'says' to you, if he's calling out 'mama', then go to him. If not, then don't. Be aware that he will also have a mantra cry which is a repetitive sound he will make as he is getting off to sleep.