Jan. 6 House select committee member Rep. Jamie Raskin speaks on the insurrection a year later

One year after the Jan. 6 insurrection, Maryland Democratic Rep. Jamie Raskin reflected on the whirlwind period between the death of his 25-year-old son and the impeachment trial of former President Donald Trump following the attack.

Raskin's son, Tommy Raskin, died by suicide on New Year's Eve 2020. The day after his son was buried, Raskin was on Capitol Hill when supporters of Trump stormed the Capitol.

"The day after we buried Tommy in a small family COVID-19 graveside service, we had the violent insurrection at the Capitol and the attempt to overthrow the 2020 presidential election by Donald Trump," said Raskin, who wrote about the experience in his new book, "Unthinkable: Trauma, Truth, and the Trials of American Democracy."

Soon after, House Speaker Nancy Pelosi asked Raskin to be the lead impeachment manager in Trump's impeachment trial.

"Speaker Pelosi asked me to be the lead impeachment manager over in the Senate for the trial, and I describe in the book, how to me that was throwing me a lifeline because I felt like I was drowning and that I might not ever do anything again," said Raskin.

Raskin told ABC News Live that he felt compelled to take the role in honor of his late son.

"I felt like I had an obligation to do it, that Tommy would be completely with me the whole way," said Raskin. "And this was a chance to try to stand up and articulate, not just my love, but our family's love, of our Constitution and our freedom and our democracy and the idea of human rights -- the opposite of everything that was on display on Jan. 6."

Raskin is also a member of the Jan. 6 House select committee and is tasked with investigating the cause and who was behind the Jan. 6 insurrection, among other things.

After a year of gathering evidence and conducting voluntary interviews, he said he's confident the committee will be able to produce results and prevent another attack in the future.

"We are getting the evidence we need in order to tell a comprehensive and fine-grained portrait about what took place and how it happened and what we need to do to make sure it doesn't happen again," said Raskin.

Unfortunately, Raskin believes that Jan. 6 wasn't the end of something, but rather the beginning. He said he's concerned about what political scientists call a "self-coup" on American democracy.

"Donald Trump decided to try to seize the presidency, and so there was a riot surrounding an insurrection, surrounding a coup against Vice President [Mike] Pence, who on that day was a great constitutional patriot and refused to bow down to Donald Trump," said Raskin. "The apparatus of insurrection is in place every day in lots of states across the country to try to guarantee the victory of Donald Trump if and when he comes back again in 2024."

Also, a year since his son's death, Raskin has become a vocal advocate for mental health. He said his son had long struggled with depression and that his son had left a note before he died that read: "Please forgive me. My illness won today."

"[Tommy] was overcome with this disease, and it's no less of a disease than cancer or leukemia," said Raskin. "Depression kills, and so we need to get people into treatment and get people the best medical treatment possible and then to continue to talk and to listen to people."