1st welcome to baby and bump.
that sounds so much like a boy thing, lol. I have three sons.
I bought mine those Braun Disney electric tooth brushes, they are alot slower than the adult ones and the brush heads are smaller and softer.
Once I bought those, my boys thought it was the best. I also bought those tablets ( harmless) that they chew up swish around and spit out, it makes all the unbrushed areas go pink. Well my boys had heaps of fun trying to brush that pink stuff off ( of course I had to do it with them).
Good luck. They do say at this age they never really brush their teeth, they more or less play around and suck on it, they will out grow that phase, trust me.