Welcome to OCF!
I have sent you a link to help you quickly learn the ins and outs of the forum. Look for the small blinking envelope next to the My Stuff tab in the top center and click on it.
Here is a list of easy to eat foods. they have a softer texture and are easier to swallow. This should help your father with his eating.
List of Easy to Eat Foods I suggest you read like crazy and educate yourself about this disease. It can be difficult to get thru the treatments but it can be done.
Best wishes with everything!