Friends are not displayed ingame, but they are
\ElvUI_SLE\modules\sledatatexts\friends.lua uses method BNGetFriendGameAccountInfo for first account only (second param), this leads to not always display friend ingame in some cases (which is incorrect - friend may be ingame, but not on first account).
Example and working (for me) implementation, which always will show friend ingame if it has game account online, in other case - showing as was implemented before: friends.lua