Thank you for your answers and Support. The BTCs are a payout from a Pool. The problem is, that they say, that my friend has to wait for confirm. My Friends transaction is a follow up with 0.08BTC in the following stairs. So that means, that they have to sent the BTC again and maybe in a few month the old payments will Fall Out of the Mempool.
Could you be more clear?
It seems to me like nobody needs to wait for anything. If someone owns you BTC, tell them to send it to you again, as this transaction is now invalid.
If their wallet is still waiting for this transaction to either confirm or disappear, then ask them what wallet are they using.
They should be able to drop that transaction and send you BTC like this transaction never happened.
If they are using Bitcoin Core, they just need to run it with argument -zapwallettxes, which will forget all transactions and the client will be able to resync the confirmed transaction with -rescan argument.