There's nothing to fix. The construction material is either of a type that does not spontaneously combust, and a carpenter can make you a fine chair out of it, or the material is the type to spontaneously combust, and if you choose to buy a chair made of that material you will soon find your pants are on fire.

If it's the former, pay a contractor to build you a chair, or make one yourself. If it's the latter, use a different construction material.

There is nothing to cure. The pathogen is either of a type that is curable, and a licensed medical professional can prepare a treatment regimen, or the pathogen will liquefy all of your internal organs within minutes, and if you choose to expose yourself to the latter pathogen, you will find yourself having a bad day very quickly.

If it's the former, pay a licensed medical professional or read online forums and do it yourself. If it's the latter, contact your nearest funeral home.