Change wallet after transaction


my friend got a serious problem (seriously :)). Beg for help. He used paper wallet, send LTC to other address, and some ammount went to a new one. I see this address, crypto stays there. I used Electrum on his wallet, did synchro, but I can see only this old wallet. To see that new wallet, I need to get keys to it. As far as I know, I should get this keys, because this address is related to previous address and whole wallet. I try to use dumpprivkey(HERE THAT NEW ADDRESS), but only got message “Traceback (most recent call last):”. What I do wrong :(?

they asked me to connect wallet to their site. I don’t trust it. Can I receive answer what to do here?

I would just use an online card with a minimum ammount of money on it, so that you can close it anytine and won’t loose money.

Screw you scammer. Burn in hell.