What you describe here yes he will go to the climbing lesson I have arranged for him on Saturdays but won't ever plan anything for himself. He is fine when we are motivating him but I'm not sure what he would do without us getting him goingis really normal for his age & stage. You need to be very careful that you are not pathologising normal teenage development
Very much agree with this.
Ds1 is 15 and very similar. Very intelligent and academic, great company, doing well in school. Does fine engaging with people generally and seems quietly content most of the time.
However, left to his own devices he will mooch, game and nap. He doesn't generally organise things, make plans or suggest places to go. Mooch, game, nap and repeat.
However he's always happy enough to go out for any meals we book. He will gently grumble about walks or some visits or activities but enjoys himself when there. He showed some interest in basketball so I joined him up to the local team to much indifference from him...but after a couple of sessions he was enjoying and he's gone twice a week now for three years.
By contrast, ds2 (13) is the polar opposite personality wise. He's on the go constantly, talks your ear off until you want to shush him, always thinking up ideas and making plans and suggestions, constantly pleading for money to go for food/to the cinema/the fair or whatever with one of his huge group of friends.
Comparison is dangerous. I have at times wondered both if ds2 potentially has adhd or if ds1 is depressed. Then I've realised neither are and the only reason my mind has wandered that way is because I'm comparing them to each other. They're just different.