Typo in a former collaborators paper

I'm currently reviewing a paper for our departments journal club and have spotted a small typo. They say 100 mm when they mean 100 µm. I pretty sure most people in the field would immediately realise this is a typo but the paper has implication for other fields who may not spot the mistake.

About 5 years ago, I collaborated with the senior author on this paper and had a good working relationship with them. We haven't spoken in a few years though. Would you contact them to point out the mistake?