Peter Ndlovu, 39, had playing spells in England with Coventry, for whom he starred in the top flight, plus Birmingham, Huddersfield and Sheffield United, before returning to African club football in 2004.
Ndlovu's former agent Winston Makamure told BBC Sport: "Peter is now out of danger. He is now conscious and is communicating. He has internal injuries, head injuries, broken ribs and a broken leg."
A spokeswoman for the Mater Dei Hospital in Bulawayo, where Peter Ndlovu was being treated, said she could offer no details of his condition, following reports he had broken both legs.
The crash that caused his brother's death occurred late on Saturday night.
The skilful attacker left Highlanders in his homeland to join Coventry in 1991, and stayed at Highfield Road until 1997.
A statement from the club, now in npower League One, read: "Coventry City Football Club is saddened to hear of a tragic road accident in Zimbabwe that has left former striker Peter Ndlovu in a critical condition and claimed the life of his brother Adam.
"It has been reported that both were travelling from an away match between Chicken Inn FC and a local side when Ndlovu's car suffered a tyre blow-out which caused the car to veer off the road 20 kilometres outside Victoria Falls.
"Ndlovu achieved iconic status during his six years with the Sky Blues where he netted 39 goals in 176 (league) appearances for the club.
"Coventry City sends its best wishes and condolences to the Ndlovu family who will be in our thoughts."