Bit of a contradiction here that seems to be promoted by the 'if it fits your macros' brigade. they try to make out that you can eat rubbish (ice cream etc) and still do well, what they seem to forget to mention is that 95% of he diet has to be spot on. Might as well keep it simple and say what you do 95% of the time is what matters, and yes you can have the occasional junk.
He does, he has rice just before training, the dextrose after training is there to cause a rapid spike in insulin combined with protein (insulin transports proteins into muscles) at a time when the muscles are most receptive (after training), no good spiking insulin before training, will make for a crap workout.