Rebecca Hilsenrath KC, chief executive of the ombudsman, said public services must be accessible to everyone.
She said deaf patients and their families should not face extra barriers when getting healthcare.
By failing to provide BSL interpreters consistently, the trust caused unnecessary distress in the weeks before Graham’s death, she added, and NHS leaders needed to learn from the case.
The former furniture maker and keen fisherman, originally from Dundee, had moved to Birmingham to be closer to his grandchildren.
He was first admitted to hospital in June 2021 following a fall and was diagnosed with heart failure.
But, after being discharged in August, he was readmitted the following month with similar symptoms and died two weeks later.
The ombudsman found that the lack of interpreters did not affect the medical treatment he received but did cause worry and stress to his family and limited his daughter’s ability to communicate with clinicians.
The trust was told to draw up an action plan, apologise to the family and make compensation payments of £900 to each grandchild and £750 to their mum.
A spokesperson for UHB said: “We offer our sincere apologies to [the family] for their experience, at what was a very difficult time for them.
“We recognise that we did not get things right and understand the impact this had on them.”
Since 2021, actions have been introduced to help deaf patients, including strengthening awareness and accessibility arrangements to ensure patients’ communication needs are better met, they added.