Not ideal training a 24 yo. Don't expect another primary pop in him for a long while.
No, it isn't ideal, but I can say from experience getting a player similar to that into a respectable/respectable really does pay off when you've got huge holes in your lineup.
Less ideal is any player with an abysmal stat where you want at least mediocre. The stamina is a prime concern. With 1 net, the stamina would take a full season just to get to mediocre. On the other hand, 2 nets would get you there in 12 weeks.
Add bat/field and you might get to resp/resp inside this season. However, with such poor stamina, you could ill afford to give him 3 or 4 nets
and play him
until he was up to mediocre, so it's a catch 22.
There might be a riskier, wackier,
it's-not-lupus style course of action. If you first give him 3 stam nets, he'll pop every 3 weeks. in 9 weeks he'll have good stamina, then you could change those trainers to 1 bat, 1 fielding and 1
wicketkeeping net, which would see him pop to respectable concentration in about 10 weeks. The risk is that the 3 fitness nets might initially burn him out, I can't quite remember what the effect is.
It might seem a bit much, but really only you can decide whether your team needs this guy to improve or if there is some better target for resources. I'm figuring in your current league such a player would be pretty unstoppable, but you could probably find useful (and more trainable, at this time of year) batsmen on the transfer market for 100k or less.