In lesson for 'ne explitif'

It's always difficult and sometimes impossible to make the English sentence sound perfectly natural across the entire gamut of English speaking nations. Let's not forget that this is a site for learning French, and the English is a way to make the French understandable, a teaching vehicle -- not more not less. It is not intended to teach English nor be a reference of the English language.

No, I'm British, and I agree with Sydney. You can't use "avoid" in this way.

Thanks for the vote of confidence, Alan!

It's just a mistranslation; éviter can often be translated as "avoid", but not in this context. "Avoid" can only be used to mean stopping oneself from doing something.

Larousse gives this for éviter que:

éviter que :   pour éviter que la mayonnaise (ne) tourne    to prevent the mayonnaise from OU to stop the mayonnaise curdling

I would more likely use 'avoid making it worse' or 'stop/prevent it getting worse' but to be fair, Collins does include the following for 'avoid' : 

1. 'keep from happening' - British English, 

2. 'prevent from happening' as American English, 

3. examples that demonstrate doing something to avoid something else happening, not just personally avoiding something. Paraphrased - the pilots took action to avoid a disaster.

https://www.collinsdictionary.com/dictionary/english/avoid 

As the statement here is in the imperative, it is a call to 'us' (to do something) to avoid it getting worse. Not the way I would say it, but not 'wrong' either. 

Perhaps I could have been clearer. I agree that all the examples in your dictionary reference are correct, but I think they fit into two structures:

1. avoid something

2. avoid doing something

I don't think you can "avoid someone/something else doing something". 

If it's not the way you would say it, and it's not the way Sydney or I would say it, perhaps it's wrong?