But that much you've found out, I think discipline and good habits are what's most important.. Let's assume they won't become great at spelling, and not waste too much energy there, but instead focus on the mechanics around avoiding it becoming an issue.
The IDE will help with what's already in the language/codebase, and assuming those are spelled correctly, autocomplete makes it hard to mess up. The problem is new names, because they will proliferate throughout the codebase, while they may be easy to refactor internally, they will be challenging when they're exposed through some API.
My suggestion is that new names are verified by searching for them on a search engine and/or using a dictionary, not only to verify their spelling, but as importantly, to verify their meaning, (I've encountered correctly spelled words that just meant something completely different because spellcheck was used, but the word wasn't looked up in a search engine to find out if it actually meant what they thought).
Newly added names that has been added, can be kept in a list for quick copy-paste access to them while being used throughout the code-base, until autocomplete can reliably use them.
Another hint during "verification" is to avoid similar looking or sounding names if possible, but that's applicable to everyone, dyslexic or not.