The Eustachian tube connects the throat and the middle ear (the site of a typical  ear infection ) and allows air to travel between them and equalize the pressures. When the Eustachian tube is temporarily pinched off, pressure can build up in the middle ear.
Visitation is a matter of state law, but generally speaking, every state allows parents to exercise a reasonable amount of visitation with their children, which generally means enough time to establish and maintain a meaningful relationship.
Visitation is typically held at the funeral home, and the deceased is typically present so that you can pay your last respects. A memorial service is a service without the deceased present. The deceased is present at a funeral service. The same rules of etiquette apply.