Excess saliva and choking

Hi girls,

So my LO is nearly 4 months old and seems to be teething, drooling a lot and all that fun stuff (not).

Yesterday my mother in law called over and when I put my baby to sleep she was saying he can choke on his excess saliva in his sleep and that she wouldn't put him on his back if she was me 🙄

Can a baby choke on his own saliva in his sleep without me noticing? Normally I would think that even if it happens he would start coughing which would obviously wake me up.

Sometimes it seems like she just wants to freak me out and make me feel more anxious than I already am as a FTM 🙄