I can't click the next button after putting the words.
What am I missing here?
There is nothing you are missing than the seed phrase is not correct, possibly as a result of mistake done somewhere, maybe while you backup the seed phrase.
I have tried with this option too. Checked BIP-39 option. I can't find my addresses, I can't see my balance there. Is the litewallet key compatible with this electrum one? I have no idea.
If the wallet generate a seed phrase in a way it is not using BIP39 standard, it will not also work just like on electrum wallet.
As long as the balance are showing on the explorer, you have nothing to worry. Your coins are there. So don't panic please.
I will also suggest OP to use blockchain explorer, or import the master public key on a wallet that support such importation (litecoin wallet should also support such) for privacy reasons. If the balance appear, yes he has nothing to worry about. But I will advice him to transfer the whole funds from the wallet into another wallet for safety reasons as he said he can still access the funds.
I have no idea why it's happening. You must miss something. Are you sure that you have the correct seed? Maybe an extra space added somewhere?
So far he is unable to successfully import the seed phrase, that means he is not having the right seed phrase like you are guessing I guessed too, but I think the guess is correct. He needs to move his funds into another wallet. And the seed phrase should be properly backup offline.