Stick with the 50.
My 17 year old went from a 30lb OMP recurve last fall to a 50lb Stryker longbow. For the first couple months he really regretted it, but now with perseverance and spending 20 minutes a night with one of these
https://www.lancasterarchery.com/sau...r-trainer.html
He is doing quite well. At the range if he does more than 1/2 dozen ends he is starting to tire...but he definitely feels ready for hunting.