Kamal Baines, 51, a property manager from Birkby is on trial charged with manslaughter after two children died in a house fire in February 2016.
Baines is accused of failing to install smoke alarms, despite repeated requests to do so.
The house fire was "eminently avoidable", had the letting agent provided smoke alarms, a court has heard.
The deaths of the young brothers, three-year old Logan Taylor and two-year old Jake Casey, may have been prevented if Bains had not allegedly neglected the requests of tenants Emma Taylor and partner Jamie Casey, to install alarms.
An electrical fault taking place in the children’s bedroom was reportedly the cause of fire.
Emma Taylor told Leeds Crown Court: ‘He didn’t seem bothered. As long as he got the rent, he was happy for me to live like that with my kids..’
Apparently, Taylor had requested smoke alarms upon moving into the rented property; as her eldest son had started a fire by putting a tea towel on a gas ring in their previous home.
‘One of the children living in the property who died was autistic. If ever there was an address to prioritise in ensuring alarms were present, it would have been that one,’ Prosecutor Allan Compton said.
A 5-minute window to save the children could have been available with an upstairs alarm, the Court was informed. Miss Taylor and intervening neighbours had attempted to reach the children but were forced back by flames and smoke. Eldest son Finley managed to escape the fire along with Taylor.
In addition to Baines’ alleged ignoring of the requests, it became mandatory for smoke alarms to be installed on all floors of rental properties in October 2015.
Mr Baines, denies two counts of gross negligence manslaughter as well as an offence under the Health and Safety at Work Act.