Best mattress to absorb movement

Hello,
My husband has Periodic Limb Movement Disorder - which is like restless legs - but can involve all parts of the body and can cause shaking movement every 20 to 40 seconds over a period of hours. When we are on holiday and sleep in beds with two separate mattresses - some zipped, some not- I find I am far less bothered by his movement. So I have been looking for zip link beds. I have also been told that any proper pocket sprung mattress should absorb his movement, and I don't need separate mattresses. He gets quite hot while asleep, and this sometimes worsens his condition. Can you make some recommendations for us? We are both 5 foot 4 and not overweight. Any information is greatly appreciated.
Many Thanks,
Lia Maxwell