It seems like he isn't using latest version which is the case here. I have tried google search and found that's the problem most of the times.
Normally i'd advice to restore your Bitcoin with provided seed/mnemonic words/recovery phrase on another wallet, but i don't whether their recovery phrase could be used on another Bitcoin wallet.
I have no idea whether trust wallet have such option to get seed, private key. I have asked him to do the same. I asked him to use electrum long ago but he didn't.