I would recommend discarding this bottle and using a new one, especially because you noticed an unidentified black material around the cap.
Ulgel-A should be kept tightly closed and stored in a cool, dry place (generally below 25–30°C). The printed expiry date of April 2027 applies to the unopened product under proper storage conditions; it does not guarantee that a bottle remains suitable after opening if there has been possible contamination.
Next Steps
If Ulgel-A was being taken for persistent acidity/indigestion, they can use the fresh bottle as directed on the prescription/package.