It is reported that after the game, Gentners father fell in the VIP area. Gentner was in the dressing room, then he crossed the mixed zone with the team doctor and the finance officer into the VIP area.
Nurses and ambulances arrived at the scene and began to revive Gentners father. The club also broadcasted requests for all fans to leave the stadium as soon as possible and for all players to stop interviewing.
Stuttgart Official Bulletin
But Stuttgart officials eventually announced that Ghentners father had died: the Stuttgart Club mourned Herbert Ghentner, the father of our captain, Christian Ghentner. He died after watching the match against Hertha Berlin on the spot. During this difficult period, the Stuttgart Club was with Ghentners family and friends.
Source: App Responsible Editor of Wanke Football: Liu Dang_NS4812