Andrew Spencer, 40, was last seen at his home address in Keighley town centre on January 9, and was reported missing on January 25.
His sister, Rosie, is leading a walk in the town tomorrow to help look for Andrew, and to raise awareness of a case she argued has been “overlooked”.
“We really just hope that he’s safe,” said Rosie.
“Police have searched rivers and woodlands and not found anything – the fact that nothing’s been found is getting a bit weird now.
“I feel like he’s been overlooked a little bit. It hasn’t been pushed in the media as much as we’d like it to have been. He’s been missing for a long time now.
“A lot of media outlets I’ve contacted haven’t been getting back to me, which is also frustrating.”
Rosie said that the police are doing “everything they can” to find her brother, but was critical of how she perceives the case was initially handled.
“By the time police got round to looking at the CCTV footage of him in the local area, it had all been wiped,” she claimed.
“I don’t think they were actually treating him as a missing person at first. But he’s had mental health struggles in the past, and that means he’s vulnerable.
“But he’s now classed as a high-risk missing person by the police and they are looking for him. I just wish they were a bit quicker.”
Rosie said she did not speak to her brother every day, but they did keep in touch regularly.
“Andrew’s a nice guy,” she said.
“Sometimes he’d come over to our house and bring a chocolate bar for my son.
“The fact he’s not been in touch with us or anyone else is making us think of the worst.”
Rosie said that 75 people have signed up to take part in tomorrow’s walk.
“We’ve been putting posters up all around town and doing everything we can to find Andrew,” she said.
“If Andrew is reading this, I’d tell him to just ring one of us and let us know you’re alright. You don’t have to come home, just text or give us a phone call to say you’re around.”
West Yorkshire Police has been contacted for a response.