In both of those, it seems that you could hire a professional and ask them how to fix it. English as a second language for professionals is an incredibly common

In both of those, it seems that you could hire a professional and ask them how to fix it. English as a second language for professionals is an incredibly common subject, he could easily find a class or hire a tutor. If it's holding him back at work then at least some consultation would be worth the cost. For your spelling, it's probably not as easy to find someone targeting you as a demographic, but I'd look for someone who does tutoring for kids with dysgraphia/dyslexia etc. There's a lot of quite specific techniques that are used based on increasing understanding of the underlying causes of spelling difficulties - if you've never learned any targeted at your weaknesses, I bet you could make a noticeable improvement quite quickly. I'd aim for someone who is using research-based methods, since there's still a lot of more folklore-based teaching around on core skills like writing.