What exactly year or date did he mine 1BTC?
There is no software that instantly mined 1BTC unless if you have a huge mining farm you can be able to mine 1 BTC but if it's just software without ASIC miner you won't be able to earn 1BTC.
If your friend has this software I believe it's fake software and you can't able to withdraw.
Thanks for your comment. My friend can't remember the name of the software so it's hard to determine if it's real or a scam. I have someone who knows the name of BTC mining software with a white arrow pointing down