Please send help!!

My sons mouth has been smelling real bad lately! I brush his teeth several times a day , including his tongue. . (It’s mostly bad breath!!) but even after he eats the bad breath comes back worse.
I’ve even added a small dot of adult toothpaste because it’s that bad.
I will be making a dentist appointment because this is bad& this shouldn’t be happening to a 3 year old.

Have y’all experienced this with your little ones??