That's kind of what I thought, that practice and repetition is the only way. Hoping someone with experience teaching ESL to this population would have a better solution.
For the a versus an, the problem doesn't appear to be the rule about vowel or consonant. I wish it were that simple. It's more like that they realize that there should be an article sometimes, but not sure when, and they use a/an some times when it should be the, and vice versa, intermingled with not using an article at all. Or using one when one isn't required. It seems like the usage is random, and certainly not rules based.
And, yes, I agree that these are common problems. They mark this very bright competent engineer as someone who cannot be used to write reports on her own or edit the work of others, and that limits her future as supervisory positions all require the ability to edit writing others have produced, and write well on ones own. The company is taking steps to have a more purposeful QC step using tech writers, but she will still be at a disadvantage if all her work costs the company more to fix than the work of other engineers does.
So, she can't get by having the same flaws as 95% of her countrymen. Not if she wants to rise up in the private sector. She will have a ceiling in our firm, I suspect. And we are one of the more flexible firms. More importantly, she wants to address this, and it seems like it should be fixable.