The family of a man who died after being restrained face down by officers has accused police of being “arrogant and evasive”, after an inquest jury found that Sussex police’s neglect contributed to his death.

The family of Duncan Tomlin, 32, have fought a five-year battle over his death in 2014. After their partial victory at the inquest they are facing a legal bill of up to £7,000, the Guardian understands.

A government-commissioned report recommended in 2017 that bereaved families should not have to pay in cases where someone has died in state custody, but the changes have not yet been implemented, according to the advocacy group Inquest.

On the day of the incident in July 2014, Tomlin’s partner told officers he was suffering from an epileptic fit but he had also taken illegal narcotics. When police were called to an address in Haywards Heath, Tomlin struck an officer and was subdued with an incapacitant spray and handcuffed during his arrest.

He was put into leg and thigh restraints and placed in a prone position with his legs behind him for 11 to 16 minutes. During this time he stopped breathing. He died two days later.

A jury at West Sussex coroner’s court found Tomlin died because of “cardio-respiratory failure due to both restraint in a prone position and the effects of cocaine and methadone”. They found the death was “contributed to by neglect” and that officers showed “no urgency” to move Tomlin on to his side.

Incidents of suspects being placed face down for prolonged periods, leading to positional asphyxia, have dogged policing for decades and chiefs have vowed to learn lessons. The jury in Tomlin’s case said police training about positional asphyxia was “inadequate”.

Tomlin’s father, Paul, said: “As a family we feel the finding of neglect by the jury is a damning assessment of the police’s behaviour. Throughout the past four and half years we feel Sussex police and their officers have been arrogant, defensive and evasive. It has been incredibility traumatic to repeatedly have to watch the footage of Duncan in the back of the police van when we consider he clearly needed help.”

The Crown Prosecution Service has already decided no officer should face criminal charges over the case, and four officers were cleared at a disciplinary hearing of misconduct charges.

Sussex police’s assistant chief constable Nick May said: “This investigation has demonstrated that officers have to make difficult judgments as part of their routine duties. Day in and day out, officers have to manage situations involving people exhibiting a variety of unusual and violent behaviour. These might be medical emergencies, mental health issues, drink or drug-related incidents, violence or very often a combination of any number of these.”