MISSING student Jack O'Sullivan's mother says things are getting "worse and worse" as his family desperately search for him.
The 23-year-old disappeared after leaving his home to go to a party in Bristol on March 2.
Police have previously said that his phone remained active on the Find My Friends app up until 6.44am.
Jack's mum Catherine said the app showed the phone was in Granby Hill in Hotwells - only a few streets from the docks where he vanished.
She and the student's dad Alan have since been searching for him and retracing his last known steps.
Jack's family have lodged a complaint against Avon and Somerset Police for their handling of the case, and a £20,000 reward has now been put up for information that helps find him, reports.
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The money was raised through an online crowdfunder, which has now brought in more than £30,000, with the family wondering how best to spend the funds to track down the missing student.
Jack's mum said: "It's getting worse and worse for us. We've changed seasons and now we are in the summer.
"You just can't believe it. Time has stood still. I am still on March 2. I can't go forward at all.
"We have to somehow find a way because we owe it to Jack.
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"If his brother was missing Jack would move heaven and earth to find him so we must try.
"He never ever takes no for an answer and 'determined' was his middle name."
Police have have been retracing Jack's last known steps by going through local CCTV and using timestamps from any calls or messages made.
Footage released earlier this year shows Jack walking around Brunel Lock Road and Brunel Way at around 3.15am.
Specialist officers have carried out various searches in the area with support from the dive team, drones and dogs.
Jack had called a friend who remained at the party he had attended at 3.24am.
But when the friend returned the call 10 minutes later, Jack could only say "hello" before the line cut out.
Before going missing, Jack messaged his mum who was expecting him to be late after meeting his friends at the party.
But when the parents woke up at 5.25am, they realised their son wasn't home.
Catherine had previously said: "I instantly knew there was a problem because it was so unlike Jack.
"We could only go by phone messages that we were getting on my phone from a family group chat and it was giving me a location in Hotwells as to where Jack was.
"So we go there and really nothing came to light, and here we are nearly 30 days after that moment with no further information or sighting."
The mum had also said spending his birthday without him was "hell on earth".
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Jack is described as white, slim build with short and brown hair.
He was wearing a quilted green/brown Barbour jacket, a beige woollen jumper, navy chinos and brown leather trainers with white soles when he was last seen.