The old adhesive on the home button bracket can not be re-used. It should be cleaned off very well and replaced with adhesive like Tesa 4695 (PET red double sided tape transparent adhesive equivalent is ok) or 61395.
Additionally with B7000 liquid glue around the bracket edges on both sides with some of it also on the rubber gasket of the home button.
This will require 24-48 hours to fully set and that’ll fit snugly.