Is he a good goalkeeper?

[John Luk]

I have a young goalkeeper and his basic statistics are in the figure

His performance is not very stable, sometimes he can make great saves but sometimes he may make own goals

Also his ability in speed is not good enough. To me, positioning, handling, speed and aggression is very important to a goalkeeper.

How can I train him to have great improvements on his speed?

[Poker-32]

haha own goals by your GK......never happend to me

But you learn him a new skill I see, maybe you should better buy a GK who has already that skill, but besides that:
Get as many green packs (savings or with tokens) and train your GK every day as much as possible.....restore his conditions with your green boosters.
But you can't choose the 'speed' by P&M......just upgrade his P&M....nothing more you can do about his speed.