I cannot really see what's wrong with that. If he's really transgender, being on hormone blockers is the best thing possible. Plus, having accepting paretings is great.
Seriously? These are little children! They cannot be transgender yet or know about the implications of such a life decision! To give some context here: The whole "gender identity" debate started with psychologist John Money* who said our gender identities are formed by society. To prove this, he conducted an experiment in which a young boy (David Reiner) who was born with deformed genitals had his penis and tested cut and modelled after female genitals - they gave him therapy, hormones, etc. Long story short, when the "girl" found out she was actually male, he/she decided to live as a man and later killed himself. That's the kind of thing we are talking about here.
Gender identity is a sexual construct and children are not sexual beings yet. They instinctively shy away from sexual things and get brutally traumatised and confused when they are forced to perform sexual acts. This was not a decision made by the child, the parents did that because they think they are "progressive". I once helped a woman who was sexually abused as a child to get into therapy, etc. You know what the worst thing was for her? That the perpetrator told her she wanted this - and she actually believed it! Because children believe anything a caregiver will tell them - their survival depends on it.
(*John Money also defended pedophilia, saying it was about "love" and had patients like David Reiner and his brother perform sexual acts with each other when they were children, to get David accustomed to his female role. When he was criticised for these things he said it was due to a "right-wing bias" in the media.)