In the video, Mr. Grodt says he joined the militia because he was committed to the Kurdish independence movement. Kurds, members of a stateless ethnic group, have been fighting for autonomy in the region for decades.
“My reason for joining the Y.P.G. was to help the Kurdish people in their struggle for autonomy,” Mr. Grodt says. He also says he wants to fight ISIS.
The Y.P.G. has become a major player in the Syrian conflict, making up the bulk of coalition ground forces fighting the Islamic State in parts of the country. Although the coalition is backed by the United States, many of the Y.P.G. leaders have roots in the Kurdistan Workers’ Party, or P.K.K., which is on the State Department’s list of foreign terror organizations.
The coalition has pushed closer to the Islamic State stronghold of Raqqa in recent weeks, trying to wrest the city from the extremist group.
Mr. Grodt’s mother said she saw her son’s decision to join the militia as an extension of a life spent fighting for what he saw as a noble cause, and a penchant for fighting for the oppressed.
She remembered when he told her that he was hitchhiking across the United States from his home in California to join the Occupy Wall Street protest in New York.
“It was hard to let him go,” she said. “I wasn’t against it but I did tell him, ‘You are a braver, more adventurous person than I am.’ He was a medic for the movement, so it was not just to be there to cause upset. He was there for the solutions.”
She said that in Syria, he hoped to be part of reconstruction of areas destroyed during battle, and he wanted to raise awareness for the Kurdish cause.
Mr. Grodt’s sister, Meghann Conforti, said he had explained to her that he would be on the front line, information he initially kept from his mother.
After Mr. Grodt left the United States, he kept in sporadic contact with his family over Facebook and Skype, and he often spoke with Ms. Dedrick and their daughter.
On the same day that it announced Mr. Grodt’s death, the Y.P.G. announced the death of two other foreign fighters: Nicholas Alan Warden, an American, and a British citizen, Luke Rutter.
Mrs. Grodt said she last spoke to her son in May. The recent intensifying of fighting in the region had made it harder for him to get in touch, she said.
The clip offers a final message to his family.
“Just know that I love you all, and there is a lot that goes unsaid,” Mr. Grodt says, before directly addressing his 4-year-old, Teagan. “To my daughter, I am sorry that I am not there.”