Can't change day and date

Even much older watches that display day and date don't require you to change yourself manually so I can't imagine this would be the case.
If the time part is working okay, bring to the jewellery store, they may have someone there to examine the mechanism. If time not working either, you probably need to wind it or change the battery

click the link below to download manual
http://support.casio.com/en/manual/manuallist.php?cid=009

• Auto Calendar (pre-programmed until the year 2039)

that means, you need to set up correct year in order to show leap years.... and then it will show you also correct day, after you will set it up correctly..... http://support.casio.com/storage/en/manual/pdf/EN/009/qw1545.pdf

check page 2

go to link below to download the manual
http://www.manualslib.com/brand/casio/watch.html#3

wind your watch forwards 12 hours

follow these instructions off the manual below if you set the watch in wrong sequens it wont change at 12 oclock
http://support.casio.com/en/manual/009/qw5125.pdfhttp://support.casio.com/en/manual/009/qw5125.pdf

On most digital watches, if you properly set the date and year, the day of the week is preset.

IN THE OUTER PROFILE YOU HAVE FOUR BUTTONS,JUST PRESS THE TIME/DATE BUTTON AND IN THE CENTRE OF THE WATCH YOU FIND THE DAY(EG:SUNDAY)IS BLINKING,JUST PRESS THE OPPOSITE SIDE BUTTONS TO CHANGE THEDATE,AFTER CHANGING DAY,AGAIN PRESS THE DATE/TIME BUTTON NOW APPEARS THE TIME BUTTON(EG:11.00 HRS),NOW PRESS THE OPPOSITE SIDE BUTTON FOR CHANGING ......
THANKING YOU.........GOOD DAY

My Dad has one of these watches, his battery is dead where can I get the battery to replace it?

Sounds like a job for the Casio service center.

If you go to "www.casio.com/support/authorizedservice", you will see the address of USA service centers.