What are the charges against a person overdose?

Yes.

It would depend if the prosecution argues that SWIM committed some act in furtherance of a conspiracy to sell the drugs, if the over-dosing person was a minor or incompetent, etc.

Yes could be held responsible for any harm done to thier friend.

Conspiracy in the crime, with the same penalties for all.

Aiding and Abetting the Delivery of drugs.

The State can bring a number of charges against a person who overdoses depending on the circumstances and the parties involved, for example. Is the person who overdosed a minor? Generally a person is liable for all the damages caused by the criminal act. In Utah, SWIM could be found liable if the Court finds that SWIM had solicited, requested, commanded, encouraged, or intentionally aided the person to engage in conduct which constitutes an offense. That person will be criminally liable as the person who committed the offense. Thus SWIM could be found as guilty as his friend who overdosed. A defense to the State's charges is knowledge. Did SWIM know that his friend was going to get heroin. The State must prove beyond a reasonable doubt that SWIM had the same mental state AND that SWIM did solicit, request, command, encourage, or intentionally aid his friend in acquiring heroin and overdosing etc.

It depends on a number of factors, but people have been charged with providing drugs which lead to death.

Yes, endangering welfare, accomplice to possession, among others.