His mother Lavinia Desuze, 31, was jailed for 18 months at the same court for perverting the course of justice by cutting up his clothes.
Desuze, 17, punched the elderly man to the ground as disturbances swept the country on August 8 last year.
Mr Bowes, who had been trying to put out a fire in a dustbin near his home in Ealing, west London, suffered brain damage and died three days later in hospital.
Desuze was caught on camera kicking in the glass doors of a shopping centre before joining a mob that attacked heavily outnumbered police with missiles.
Wearing sunglasses and a distinctive top saying 'Robbers and Villains', he threw his full weight behind a punch to Mr Bowes' jaw, buckling his legs and knocking him unconscious.
The pensioner fell backwards on to the pavement and his head took the full
force of the impact.
Prosecutors said police were "simply unable to reach Mr Bowes for some minutes
because of the violence against them".
Speaking outside the court, Anne Wilderspin, Mr Bowes' sister, said: "I was devastated by his untimely and unnecessary death."