June Knight, 79, died on Monday at Langley Lodge Nursing Home in Westcliff-on-Sea, Essex.
Robert Knight, 52, will appear at Southend Magistrates’ Court on Wednesday charged with her murder.
Police said the man charged, from Leigh-on-Sea, is related to Ms Knight but would not give any more details.
A post-mortem examination will take place this week.
The nursing home said it was “utterly shocked by what happened”.
Essex Police said officers are not looking for anyone else in connection with the death.