Delyth Andrews, 54, died after a seven-hour attack in which the brothers performed violent throws including rainbow flips, T-Bones and Cliff-hangers on their victim.
Scott, 23, Adam, 20, and 19-year-old Joshua Knight, took Ms Andrews prisoner in her Ramsgate home after claiming to have smoked legal highs.
On Thursday, they were jailed for a minimum term of 23 years but warned they may never be released from prison..
Judge Adele Williams said: “In my judgement they are equally responsible, equally guilty.”
The jury at Canterbury Crown Court took three days to find them all guilty of murder.
All three men denied murder. Joshua and Adam offered guilty pleas to the lesser charge of manslaughter and all three admitted causing grievous bodily harm with intent before she died.
Adam Knight’s defence Johnathan Higgs QC, said: “She was abused in her own house and during the preceding months these three invaded her home and abused that trust.
"There was an absence of understanding by the brothers about what they had done."
Philip Bennetts QC, prosecuting, said that Delyth's neighbours had described her as "too trusting" after she died following the attack, in December 2015.
The court heard that Delyth, who was described as 4ft 11ins and suffering with bi-polar disorder, got to know the brothers after inviting their homeless mother, Elaine Morley, to live in her home in Ramsgate, Kent.
Mr Bennetts added: "Joshua moved in as well - and as time progressed, Elaine Morley's other sons, Scott and Adam also moved into Ms Andrews's home.
Within weeks, they had stripped Ms Andrews’ semi-detached home bare of everything they could sell to buy drugs.
The court heard that the family were "noisy, anti-social, playing loud music which was going all times of the day and night".
An X-ray revealed she had multiple rib fractures, fractures to her sternum and her pelvisMr Bennetts