Its hard to describe but my button gets warm slowly after 5 five decent hits is that normal or is it a problem with the switch its self iv read it could be as simple as a crappy spring
Might take it to a B&M Vape shop and have them comment.
The tricky part is how will he know his B&M is trustworthy and knowledgeable about his mech mod issues?If you have a decent B&M near you that understands mods, it might be worth it for your peace of mind...
In your shoes, I'd travel to a trustworthy B&M if I had access to one.
Having said that, I know a warm or hot to touch fire button on a mech means trouble. I won't even get into a discussion of what could be causing the problem, because I'm not that much of an expert on mech mods.
What batteries are you using? You're coil resistance is pushing the amp limit of even the best batteries for a mech.