Andy Murray's father-in-law Nigel Sears is "conscious, talking and sitting up" after the 58-year-old collapsed at the Australian Open, Jamie Murray said.
Sears, also the coach of Ana Ivanovic, was in Rod Laver Arena for the Serbian's third-round match against American Madison Keys when he collapsed and had to be carried away on a stretcher.
The match was suspended for 50 minutes while Sears was taken to hospital, where it is understood he was seeing a cardiologist.
Jamie Murray told Press Association Sport that Sears was "undergoing tests" but was "conscious, talking and sitting up".
Andy Murray continued playing his round-three tie against Joao Sousa on Margaret Court Arena, apparently unaware of the incident.
Sears received swift medical assistance and Australian television station Channel Seven reported the 58-year-old had to be carried away with his shirt off but was conscious.
Ivanovic and Keys waited on court for around 10 minutes before they were informed play was suspended and left the arena.
After a 50-minute delay, the players re-emerged and the match was resumed with Keys trailing 6-4 1-0.
Sears' daughter Kim, Murray's wife, has remained in the UK during the tournament as she is expecting the birth of her first child, which is due in February.
This is Sears' second spell working with Ivanovic after he was reappointed as her coach in July last year.
He has previously worked with Slovakian Daniela Hantuchova and also as captain of the British Fed Cup team.