Crushing medications for those who have difficulty swallowing is a common practice in health care. However, there are cautions that must be considered when crushing medications. For example, some medications may interact with each other by either having an additive effect or causing less absorption of another. Others may release a large amount of medication at one time.
Before you crush any medications, talk with a pharmacist about using jello or any other food or drink. Most medications can be crushed and put in juice, water, or pudding. For the medication that cannot be crushed for whatever reason, talk with your doctor or pharmacist to see if the medication comes in a different form. There are liquids and sublingual preparations that may be more suitable for your father.
You may also want to consider purchasing a pill crusher and make sure that the pills are smashed almost to a powder. This might help your father to tolerate the medication better.