“Rule number 1: Fuck what they think.”

This advice can be found on Robert Mugabe Jr’s Instagram account, squeezed among photographs of him in sharp suits and expensive trainers; trendy club pics and fancy ride pics and the explicit, often misogynistic memes he finds so amusing.

Judging by their big-spending, hard-partying lifestyles, it is advice Robert, 24, and his brother Chatunga Bellarmine, 20, have taken to heart.

The brothers, who don’t work, live in a Sandton apartment (they were kicked out of another one in April after being involved in a violent brawl. That one reportedly cost them more than R70 000 a month). They are regulars in Jo’burg’s most upmarket clubs, where they order top-end alcohol and pick up the tab for entourages of up to 20 people.

They know, as sons of Zimbabwean President Robert Mugabe and first lady Grace, rules don’t apply to them.

“Their aides don’t even want bouncers to ask for ID when they get to the door. They say: ‘Don’t they know who our family is?’ ” a security manager at a club in Johannesburg said on condition of anonymity.

A club promoter who works with Taboo in Sandton and Kong in Rosebank told the Mail & Guardian that the Mugabe sons often entertain groups of women. They order imported Armand de Brignac or “Ace of Spades” champagne (R6 500 a bottle), a favourite of hip-hop mogul Jay-Z, as well as Moët & Chandon and Belvedere or Ciroc vodka.

“Whenever they arrive at the club the girls know the [brothers] are picking up the tab, and it’s only top-class drinks,” said the promoter.

Private VIP suites are the norm.

“They can’t be expected to wait for drinks like the rest of the people in the club. They have aides that handle everything, from guests to sit with them and paying the bills,” he added.

Although Robert and Bellarmine might not care what anyone thinks, their lifestyle has been heavily criticised back home. As Zimbabwe goes through yet another economic crisis – precipitated by the poor policies of their father’s government – his sons can spend more than the country’s annual gross domestic product per capita (R13 289) in a single night at a single nightclub.

Neither son replied to requests for comment, made via social media.

“The sons are crazy,” said a senior Zimbabwean diplomatic source. “What is said about them is a fraction, an understatement.”

Even their parents are embarrassed. The sons were sent to study in Dubai, in part to prevent them from misbehaving in Harare. That ended in controversy, with some media reporting in 2016 that they were asked to leave. So they were moved again, this time to Johannesburg.

“The [first family] is running out of options. They can’t afford the sons to come home, but where else can they go? Dubai is not an option now. Europe is out, America is out [for political reasons]. South Africa is the last chance,” said the same source.

Johannesburg also features in the Mugabe seniors’ long-term plans. It is a potential bolt-hole in case the Mugabes are no longer welcome in Zimbabwe. Grace is setting up her own R45‑million home in Sandhurst, according to a report in The Star.

She has also made repeated visits to Johannesburg to settle her sons.

But she is not exactly a stabilising influence. She burst into the headlines again this week when she was accused of assaulting Gabriella Engels, a 20-year-old model, in a hotel room rented by her sons. Grace allegedly beat Engels repeatedly with the plug on an extension cord as her bodyguards watched.

Although Engels has laid charges, Grace has invoked diplomatic immunity to avoid appearing in court.

The Zimbabwean High Commission did not respond to requests for comment, and there has been no official statement from the Zimbabwean government.

Zimbabweans, all too familiar with their first lady’s erratic behaviour, are not surprised by the new allegations. Her reputation precedes her. There’s the lavish spending; one day in 2003 she reportedly dropped £75 000 on luxury goods during a shopping trip in Paris. There’s the obvious disconnect from the reality of everyday life; the day she donated a bag of men’s size 13 shoes to an orphanage, posing for a photograph with the orphans as their tiny feet struggled to balance in the enormous, impractical footwear.

And there’s the violence.

In 2009, British photographer Richard Jones accused her of assaulting him outside a hotel in Hong Kong. According to Jones, her bodyguards chased him and attempted to take his camera. They then pinned his arms down while the president’s wife punched him repeatedly in the face.

Earlier this month, Grace was allegedly detained briefly in Singapore after attempting to destroy camera equipment belonging to two journalists. Mugabe had accompanied her husband to the Gleneagles Hospital in Singapore where he was being treated for an undisclosed medical condition.

In both incidents, Mugabe’s diplomatic immunity protected her from investigation or criminal charges.

It’s not just outside Zimbabwe that the first lady has a track record of behaving badly – although her status means it can be dangerous for Zimbabweans to speak against her, or for journalists to report on abuses that happen inside the country.

“There is a disturbing trend of allegations about Mrs Mugabe’s penchant for impulsive and violent reactive behaviour. Such an approach to ‘problem solving’ will inevitably raise questions about her judgment, which in turn has implications for her suitability for political office,” said Piers Pigou, a political analyst with the International Crisis Group, referencing the first lady’s barely disguised ambition to succeed her husband.

Despite this, her sins pale in comparison with those of the man who holds that office: Mugabe, Africa’s longest-serving dictator, who has been implicated in serious human rights abuses throughout his 37 years in charge.

Like father, like mother, like sons. Zimbabwe’s first family is also its most dysfunctional.