Arf at DM dropping into paragraph 3 that they live in a 'television-free home'.
That confirms it then, incase readers needed any extra evidence, they're totally bonkers 
Fwiw, each to their own imo. However, leaving him open to ridicule (dressing him in girls uniform) when he isn't old enough to stand up for himself against those who will believe he should conform to gender stereotypes (his peers) is bloody cruel. Regardless of whether or not we should have such stereotypes, they do exist and other 5 year olds will think he's strange and I think, because he has been brought up unaware of such things, he is going to be utterly baffled by their reaction and possible rejection.
Also agree that gender neutral does not = dressing him in pink flowery clothes. Surely it should be plain tops and jeans etc? Non-identifiable of gender clothes, no?