Late last year, Jayden Burleigh reflected on the devastating death of his little brother Lachlan in a triple fatal car crash in the Blue Mountains.

"Let your little light shine Lachie Burleigh. I miss your physical presence like nothing else," Jayden wrote in an online tribute to his 17-year-old brother.

"My little bro man, thank you for giving me that special strength. It's just really hard for me right now trying to fathom turning this into a reality."

Now, the Burleigh family from Warriewood on Sydney's northern beaches have been dealt another crushing blow, following the unexpected death of Jayden, 22, on the weekend, a short time after he was hospitalised for a redback spider bite.