Ryan Greenlaw was a devoted father and loyal friend.

Among the most important things in Ryan Greenlaw’s life were his two daughters.

On a hot summer day when his girls were younger, he created a makeshift swimming pool in the back of his pickup truck. He covered the truck bed with a tarp and filled it with water, which was very cold – but his girls loved every minute of it.

“They were laughing so hard,” said his mother, Maureen Greenlaw of Biddeford. “They even went in a few times. Only Ryan …”

Mr. Greenlaw, who lived with his mother, died Sunday at her house of a suspected heroin overdose. He was 37.

He was remembered this week as a devoted father and loyal friend who had a big heart despite his years-long struggle with addiction.

Mr. Greenlaw grew up in Windham. As a kid, he was into wrestling and once competed in a youth wrestling tournament in Ohio. He attended Windham High School and obtained his GED in 2010.

Mr. Greenlaw painted houses in southern Maine for several years. He briefly worked for Artas Designs in Biddeford.

His father, Gordon Greenlaw of Saco, said his son had a strong work ethic, but his focus was always his daughters, Maria Greenlaw, 14, and Kayleigh Greenlaw, 12.

“He loved his girls more than life,” his father said. “He was bigger than life. He had a huge heart. People loved him. He just couldn’t put his life together, that’s all.”

Mr. Greenlaw started smoking pot at age 13 and progressed to heroin. His struggle with addiction cost him relationships, jobs, his freedom and eventually his life.

His parents expressed anger, shock and sadness Tuesday. His daughter Maria turned to Facebook to share her feelings about her father.

“I love you so much,” she wrote. “I can’t believe that you’re gone forever, but you’ll always be in my heart. I will always know that you’re with me.”

Mr. Greenlaw’s father said his son knew where to get help. He believes the stigma of addiction may have kept his son from doing so.

“Once you say it, you always are,” his father said. “Get help. It’s probably the toughest decision you’ll ever make. It will be the best decision you ever make.”

Corey Stevens will deliver the eulogy for his best friend at a celebration of life from 1 to 4 p.m. Saturday at the Sahara Club, 57 Ashmont St. in Portland. Stevens said through Facebook messenger Wednesday that Mr. Greenlaw had a heart as big as he was.

“He was always going out of his way to please the people around him, even if that meant it made him vulnerable to ridicule or manipulation,” Stevens wrote. “I don’t think he ever let that stop him from his goal of putting a smile on someone’s face. I loved Ryan with all of my heart, though sometimes he frustrated me with his choices, especially later in life. But he was a rock that I knew I could cling to in the event that I ever needed anyone. He depended on me as well. We had that bond. There were no rules to our friendship.”