why you can see the balance and check the private key, do you want to steal other people's assets?  your question is not clear. If you want to seek help, include a website, or a photo that you've lost assets, so everyone here can help. if like this, you will be accused of stealing, and looking for solutions to take other people's assets. there is no good method to check someone else's private key, but you can only see other people's assets, such as tokens and coins through his wallet.