Send Email button is not visible when sending Approved Emails from Medical Events in CRM iPad.
One reason is that the user has no access to any Accounts of the Event Attendees.
This could be a data issue if the user lost access to the Accounts after adding the Event Attendees.
Be sure the user has access to the Accounts in Event Attendees.
Please refer to Event Attendees for more details.
CRM Help Documentation: Sending Approved Emails from Medical Events