(CNN) Daniel Johnston, an eccentric singer-songwriter and advocate for mental health awareness who developed a strong following among other artists like Kurt Cobain and Tom Waits, died early Wednesday at his home outside of Houston, according to Tom Gimbel, Johnston's manager of over 25 years. He was 58.

"He's just an inspiration. I think he was a true genius," said Gimbel.

Johnston's family and Gimbel said he died of natural causes.

"Daniel was a singer, songwriter, an artist, and a friend to all. Although he struggled with mental health issues for much of his adult life, Daniel triumphed over his illness through his prolific output of art and songs," a statement from Johnston's family read. "He inspired countless fans, artists, and songwriters with his message that no matter how dark the day that 'the sun shines down on me' and 'true love will find you in the end.'"

Johnston got his start in Austin, Texas, in the mid-1980s, attracting a small following who became fans of his homemade cassette tape recordings.

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