When we were talking to the ped today, he told us not to let LO sleep flat at all, to keep him upright at all times like in a car seat. We have a Mamaroo but I don't think he'd tolerate it for too long, and I can only put his bassinet/crib mattress at a slight angle before he starts rolling into the corner. (The issue is that his reflux is causing apnea.)

Is there anything else you can think of that we should try?