Sourdough starter smells like acetone

Almost certainly not. An acetone smell means the yeast and bacteria have eaten through their flour and are hungry, not dying.

1. Discard all but 50 g.
2. Feed 1:2:2, so 50 g starter, 100 g flour, 100 g water at about 26°C.
3. Repeat every 12 hours for two days.

If it doubles within 6 hours of a feed, it is ready to bake with again.