The public key that starts with TMWgDA5 and end with 3zJK7No is 34 characters long.
The other key - which I think is an associated private key is in Hex and 63 characters long (perhaps a leading 0 missing to make it 64 characters long) - it starts with 73cedc8e7 ... and end 10dc7078
Yes, as said by @asriloni
That is Tron's wallet address. And please check whether he had a Tronlink wallet or not.
And for the private key, never tell anyone else whether he is willing to help you, never trust everyone that asks about the private key.
And you can now start to learn about the Tron wallet.
Yes, the private key should include 64-bit hexadecimal characters.
You can try to log in on the Tronlink or in
https://tronscan.org/ (but ensure that the private key is correct) because missing one character means you may not be able to log in.