My father in law is on life support from a drug overdose and his kidneys are shut down. Will he ever b the same? He was unresponsive w/ bed sores also

Looks grim. The presence of bedsores suggests a long-term problem. The drug overdose causing both a coma and kidney failure suggest mult-system organ failure. Occasionally, this can be reversed by an emergency dialysis, but the combinanation is very worrisome.
Difficult to say. The fact that he continues to need life support may mean other problems beyond the drug overdose. The overdose itself would improve once the drug was metabolized "burned up" by the body. Prolonged symptoms can occur from other complications. If one has a cardiac arrest from the overdose for example, the brain or kidney can be injured. It sounds like you need to talk with his doctors to clarify.