Matthew performed better than Brady everywhere, and he also significantly outperformed the expectations during his NHL career, which is a factor even if Brady didn't reach that point yet.
But if we just go by production:
u17 season:
Matthew: USHL 33gp 17p, USDP 53gp 33p
Brady: USHL 32gp 8p, USDP 55gp 25p
u18 season:
Matthew: USHL 24gp 33p, USDP 65gp 95p
Brady: USHL 24gp 23p, USDP 61gp 54p
u19 season isn't comparable, but I guess you just need to take my word for it that scoring at 1.9 PPG in OHL is more impressive than scoring at 0.8 PPG in NCAA.
Matthew also scored better in every equivalent international tournament.
As for things other than scoring, Brady's skating is better. But that's about it - The biggest difference might be in hockey IQ and positioning that are significantly in Matthew's favor.
I'll call it a miracle if Brady goes to NHL next season and scores 50 points.