]Being loyal to one's family was still a crucial cardinal value in Henry's time.

I can't argue with this and is perhaps an excellent explanation for his actions but this is not the problem for me. The issue for me is that in being loyal to his brother, if he felt that is what he needed to do, it still does not justify: since I don't want to criticize my brother, it is therefore Isabella's fault.

]this does not in any way suggest that Henry did not condemn Frederick's behavior inwardly.

I believe this completely. Henry knows his brother is wrong but he takes an outwardly cavalier attitude toward Frederick's behavior, IMO (a boys-will-be-boys kind of thing) while censuring Isabella and, belive me, I am no fan of hers. It's one thing for Henry to feel he needed to be loyal to his brother, (though it seems to me, in the process, he was not as proportionally understanding to Catherine being loyal to hers), and another to have no problem with condemning Isabella when both Isabella and Frederick were engaging in improper behavior. [A narrative aside: So Henry, either blame them both, absolve them both or leave it alone.] Just think---if he had remained neutral, he could have been the perfect Henry. Alas! ;-)