Conversation so far:
What led to Kai Hansen and Michael Kiske's departures from Helloween?
Guitarist Kai Hansen unexpectedly left the band in 1989.
Why did Michael Kiske leave Helloween?
Conflicts within the rest of the band worsened, with Michael Weikath refusing to work any longer with Michael Kiske. The decision was made to fire Kiske.
Did Kai Hansen give a reason for leaving Helloween?
Kai Hansen left due to ill-health, conflicts within the band, troubles with Noise International, and a growing dissatisfaction with life on tour.
Who replaced Kai Hansen in Helloween?
Weikath chose his friend Roland Grapow to replace him.
Who replaced Michael Kiske in Helloween?
Helloween returned in 1994 with Andi Deris as their new lead vocalist and Uli Kusch on drums.
Are there any other interesting aspects about the Helloween article?
Abdel-Nabi's inability to replicate Schwichtenberg's machine-gun style of drumming hindered Helloween's ability to play live fan-favorites.

Question: What did the band decide to do then?
Self-contained rewrite: What did the band decide to do about Abdel-Nabi's drumming problems?