how likely is that the hacker succeed in put the words in the correct order and steal the funds?
Very, very, very unlikely. You could input all the words on a fully infected computer and as long as they're not in the correct order it would be impossible to guess the right one. Indeed that's how you restore a Trezor one. There are just too many combinations for it to be a realistic possibility.
As ever there'll be some slackness on their part that they won't be alluding to.
It's something like ~2^70, can be feasible to crack for someone with deep pockets, but not in this scenario when you don't know how big the payout is. However, this is assuming a good random permutation - if it was a human-generated and not full permutation, which is most likely the case - i.e. the OP said they swapped the last and the first words, and some other words, then the task becomes very doable.
This story is really sad, it shows us that humans are very prone to errors, and that Bitcoin severely punishes people for their errors - no matter how little or many coins you have, one mistake is enough to lose them forever.