Potty training

Fran
Hi everyone! I'm currently pregnant with my second boy. My first boy is 3 and STILL not potty trained. He doesn't talk as he should at this stage so I know that's a factor but he has absolutely zero interest in using the potty. He actually cries hysterically when we try to show him. I've tried putting regular undies on him and he just goes right through them. Like it doesn't even bother him that they're wet. I tried sitting him in the toilet to just go and he went a few times one day but that was it. I don't know what to do, I'm literally in tears bc I don't want to have 2 kids in diapers. Idk what to do! HELP!