Potty training a stubborn toddler

My son is 2 years and 4 month old. I want to potty train him as he has very sensitive skin and diapers even organic ones don't help now. For the mamas that might say make sure you air him before putting diapers on him, Yes I do that and even I bought a small portable fan the I use one him. So what I do every time I change him is that I sit him on the toilet( I place his toilet chair) then I wash him with water, I use a muslim towel to dry him, then use a fan to make sure he is aired, put diaper cream on him and last put his diaper.

For the mamas that will say make sure to change him immediately, Yes I do so, I check him every hour to make sure that I'm not late.

I just think it is better for him to go to the toilet to prevent the diaper rash and have his skin safe. The thing is my son is stubborn, when I try to talk to him about the potty or show him that he should do this here, he will look at every inch of the bathroom so that he can tell me that he will not listen.

He has a speech delay and he goes to speech therapy now. I really don't want his speech to be the thing that is the excuse that he can't be potty trained.

He can and I know he can. I noticed that his diaper stays draly for a long time. I think this is a good sign.

I really need some help and advice with this.