The late Ram Bulchand Jethmalani was born on Sep 14, 1923 and thus passed away a few days short of what would have been his 96th birthday. While formerly a Rajya Sabha member of the BJP in 2010-16, he was now representing Bihar on an RJD ticket. He was the oldest Rajya Sabha member at this time, and may well have been the oldest ever Rajya Sabha member.
Here is the “seniority list” of current RS members:
The oldest member now is Motilal Vora at 90, followed by Manmohan Singh a little short of 87.
In the present Lok Sabha, the oldest member now is Shafiqur Rahman Barq representing the SP, from Sambhal (UP). He is 89.
While HD Deve Gowda did not get elected to this Lok Sabha, he is younger than Mr Barq as he is now 86.
In the previous Lok Sabha, the oldest member appears to have been LK Advani, born in Nov 1927 and was thus 91+ at the time his term was completed in May 2019.
Coming back to the Rajya Sabha, older references mention the oldest member to have been Rishang Keishing of Manipur, who was 93 when he left the Rajya Sabha in 2014. He had earlier been the Chief Minister of Manipur.
So it appears that Ram Jethmalani was the oldest ever member of the Rajya Sabha, and perhaps the oldest from both houses of parliament.
His daughter Rani was also a lawyer of some repute, but had passed away in 2012.
There would be several parliamentarians who lived to a greater age, such as Morarji Desai and Gulzarilal Nanda who both crossed 99.