I’m not a huge Cash fan but dude had some rough times with addiction. Alcohol, amphetamines, barbiturates…
It likely cost him his first marriage and he struggled with it his entire life. The movie “Walk the Line”, about Cash, features his substance abuse quite prominently.
https://en.m.wikipedia.org/wiki/Johnny_Cash#Personal_life
Throughout their marriage, June attempted to keep Cash off amphetamines, often taking his drugs and flushing them down the toilet. June remained with him even throughout his multiple admissions for rehabilitation treatment and decades of drug addiction.
Dude also died less than a year after filming the music video, shortly after his (second) wife, June.
Reznor and Cash both struggled with addiction and guilt for the damage their addiction caused to those they cared about.
Fundraisers and charities, when you have a lot money, are rarely acts of charity. They tend to be PR campaigns and power plays.
Honestly, even when the acts have good intentions, they are often quite damaging. The involvement of the wealthy in charity is very similar to their involvement in politics. Their wealth buys influence and gives them a disproportionate say that allows them to ignore and overrule the will of the people and sometimes even reality.
For example, look into the impact of Bill Gates’s “acts of charity” in the education space. He poured money into charter programs that negatively impacted public education. Later studies showed that his programs were not particularly effective.
Let’s say, hypothetically, that a very rich person is convinced by some charlatan that they found the a means to produce free energy. The wealthy person throws tons of money at the idea. How many talented people will be taken from other legit programs because the paycheck at Bullshit Energy Nonprofit is better? These rich people are successful and think they know bestr. Their money ensures they get treated like experts because money makes things happen whether or not those things are helpful.