Jimmy Guichard, of MacKenzie Way, Gravesend, was cremated following a service attended by more than 70 friends and family.
The 20-year-old's mother, Karen Audino, said: "Some people couldn't make it, but I was so overwhelmed by the amount of people who did."
The funeral of Jimmy Guichard who died a day after apparently taking a legal high
The A2 was partially closed because of the storm, which blocked the funeral procession's route from Gravesend on Monday.
Through her tears, 42-year-old Karen joked: "Trust Jimmy to be late for his own funeral."
A keen sportsman, Jimmy was laid in a white coffin with the English and Irish flags as well as his Donegal hurling shirt draped over it.
Here I Am Lord sung by Daniel O’Donnell, Jimmy’s favourite song, Numb, by Linkin Park and I'll See You Again by Westlife were played during the service at Eltham, as was The Old Rugged Cross – a family tradition.
His sisters Sam and Katie and father Martin prepared poems, but were too overcome to read them so friends and family stepped in.
Jimmy Guichard in hospital shortly before his death
Karen said: "I didn't think I would be able to read my eulogy. I sobbed my whole way through."
Breaking down in tears, she added: "That boy just didn't know how much he was loved.
"I'd just like to thank everybody for their support and their kind phone calls, texts and Facebook messages.
"Especially Jen Kelly, who is like another daughter to me and opened her home to me."
Jimmy, brought up in Dartford, was living in Gravesend and is believed to have taken the legal high just hours before suffering a heart attack.
The funeral of Jimmy Guichard who died a day after taking a legal high
Karen is in talks with local MPs and has set up a Facebook campaign to have the substances made illegal.
A post mortem examination has been carried out and the family are awaiting the results.