Checking out the HBO guides (1, 2, 3 ), I see that Willas and Garlan only seem to be mentioned on the first season Tyrell family tree, and have "disappeared" from the latter two seasons. I don't know if they were ever there in the first place, or if there is another official spot somewhere that might mention one of Loras' 'older brothers.'
There is talk on Shireen Baratheon's page of a similar removal of that character (and subsequent re-addition), although I can't find any link to the Season 1 Baratheon family tree that mentioned her, implying that HBO has streamlined the pages since then. From the latest episode ("The Climb"), Tywin outright states that Loras is the only heir to Highgarden, and his vows to the Kingsguard would place the inheritance in the lap of Margaery (e.g. King Joffrey).
This *implies* that Garland and Willas have been completely written out. It's possible that they're deceased, crippled-beyond-repair, swore their own oaths elsewhere (Maester/Night's Watch/Faith of the Seven), or any other wild speculation. We probably shouldn't delete these pages, but should they be rewritten to acknowledge that HBO appears to have only toyed with the idea for a second? Maybe relegate them only to background sections until we receive some more information on them.
Again, this is assuming I'm not missing some featurette or DVD list or something that goes into further detail and supports or contradicts "The Climb"'s assertion that no other heirs to Highgarden (before Loras and then Margaery) exist.--Tim Thomason (talk) 02:37, May 6, 2013 (UTC)