Really confused

[Memeto3boys]

I have a 2 year 8 month old son. Still in nappies full time. I have read got advice off HV about potty training but I am still confused.
He very rarely knows he's wet or dirty. He will say he's weeing and pooping when he's not and when he doesnt have a nappy on its clear he's no idea at all that he's peeing or pooping. He also poops from 3 to 4 times a day never regular. He sits on the potty loves doing so but only for seconds he will sit making a hissing sound stand up and pretend to flush it. He shows interest at using a potty and even tries to encourage his 19 month old brother to try. He doesn't like being dirty or wet and when he has had accidentsome when he's had no nappy on waiting to go in Bath he's got incredibly upset. He's even pooped in the bath a few times. Do you think I need to discuss with the doctor that he seems to have no feeling at all? Should he have some sort of feeling by now?