I think it depends how we define "big brotherly." Baden Powell has a similar quote that I think is easier to understand. “To get a hold on boys you must be their friend.”
The YPT rules have definitely made communications between adults and youth restricted. We cannot communicate or interact with our Scouts like they do their peers in the troop or school. The YPT rules have made it impossible for adults to have "private" relationship with a Scout that nobody else is aware of, and that's a necessary safeguard. As @DuctTape said, "in the spirit of." I believe very strongly that how the YPT rules are written gives me the necessary operating room to ""Guide the boy in the spirit of an older brother" or “be their friend” while still observing YPT. More or less, what I think BP means by both quotes is a Scoutmaster shouldn't be a drill sergeant, strict teacher, or stern parental figure.
Part of the challenge is that it's challenging to define some of these terms in a scouting context: "Personal" "Private" "1 on 1."
I also think it's very possible to have "personal" relationships with Scouts. I don't have "secret" relationships with them. I talk to my Scouts, I get to know them. They get to know me, my experience in Scouts, and some details about my life and profession. There are certainly some topics that are off limits for me and for them. There's definitely some jokes and good natured teasing that goes on between them and I. I know their goals in Scouts, and their interests outside of Scouts. Sometimes they come to me with very personal things or they want my opinion on something. As much as possible, and depending on the nature of their request, we'll discuss those things out of the earshot of others, but in view and knowledge of other Scouts and Scouters. I grant that this could be because I'm closer in age to my Scouts and I have an easy time relating to them. I follow all the YPT rules exactly as they are written. If anybody is confused how that works, and why I feel like I'm within the rules, I'll explain, but I feel like we've beaten to death the YPT rules on this forum.
Many of my former Scouts stay in touch when they age out of Scouts. If that's not the result of guidance in the spirit of an older brother; then I'm not sure what is. I feel like this is likely true for most of us here.
As for the Scouters Motto I like: "Train 'em, Trust 'em, Let 'em lead."
I always found this to be the most interesting question by the EBOR because the answer typically shows how the scout feels about his culture, and often shows me that I (the scoutmaster) didn't know him as well as I thought I knew him. As was said, there is no right or wrong answer, but usually enlightening. At least for me.
Eagle BoR are different from other rank BoR in my district due to the fact that other rank BoR are done by persons that know the scout on the unit level whereas the members of the Eagle BoR may not have ever had any dealing with the scout. There have been many Eagle BoR that I have been a member of that the board as not even asked the scout to say the scout oath or the scout law. But one question we almost always ask is one of the following. " There are 12 scout laws if you had to remove one of the laws which one would you remove and give your reason why you would remove it for the law.' or what law would you add and give your reason." There is no right or wrong answer but as a board we are trying to get a feel for the scouts thought process.
Depends on the Scout's reply.
If it was "Sorry for the omission, please let me try agian." --- that suggests to me that he is living by them.
If it was:
"Well, I don't think a scout really needs to do all of those things."
or it was:
"Correction, a cuttlefish is ..."
or any such variation ... --- that suggests that there's one or more that he'd rather not live by.
The Oath and Law are no mere shibboleths. If you advance the snake who says them masterfully, but you know he's refused to live up to them in his daily life, you're doing nobody any favors.