Hi, i suppose my question is 'what do you want?'. In truth you don't know the details of his personal life because, at this point, you don't appear to have the kind of relationship where you confide in each other. Is this what you would like? If so, as others have said then small steps, not the big heavy questions straight away.
As the eldest (or oldest??), i was considered 'hard work' and 'difficult' which is now acknowledged that i was actually just a normal horrible teenager!
My siblings, some 6/7 years younger i viewed (then) as a complete pain and the dramatics I could go into are stuff of legend. 'They touched my things/been in my room' i would gasp 'I hate you all' i would thunder and Mum says she was amazed our house still stood after my door slamming phase
Mum and I had, and still do occasionally, have a fractious relationship. As siblings we all are now grown up (allegedly) and are hugely supportive of each other, respecting each others personalities. They do not hold against me the horrible things i said as a teenager - thank goodness; they laugh about it and said it was good training for having their own children
I wish you well with your counselling and it is natural to be curious about a siblings view of their childhood, however we are all different and his view may be very different to yours. Hopefully you can build a relationship with your brother moving forward, however my impression is you have a rather negative view of him, which he will possibly sense and this could affect his willingness to engage.
Take care.