Does flashing cards for word recognition for a 5 year old still work? I have a 2 year old which I can start on flash card method (ie Little Reader) but not sure if I can also get her older brother to join. Any experience with that?
In my opinion, if he is interested, let him watch! Even if he isn’t interested, you might convince him to “help” the younger one learn by pointing to the screen and repeating the words as they are spoken in the curriculum. He will especially gain from the phonics sections!
LR can be adapted so much to be useful to any age. You could download categories that he is interested in from the library and make his own lessons! Have you had a chance to look through the library yet? 
The flashing method definitely won’t hurt him. The more often he sees the words written while hearing them read, the more likely that he will pick it up. Good luck! And keep us posted!
Thanks CV Momma! My older one definitely gets the phonics bit and he is now more “responsive” to the words and pictures shown.
(and I think he has some competitive spirit and wants to learn more than his sister - not sure if that’s good or bad, but at least that is a motivation for learning)
I second the recommendation to try it with your 5 year old. If interested, he may really absorb the information…especially if it’s subjects he’s interested in. You can also create personalized books in BK or even in word.