Drug to supplement interactions are not well known because they aren't well studied. No one has a financial motivation to do so. Most conventional doctors will not be aware of drug to supplement interactions, or be interested in researching them. This is my experience. That said, there is an interesting AARP link on potential drug interactions with Capryic Acid.http://healthtools.aarp.org/natstandard ... rylic-acid
Natural Standards is a well regarded source of information on "natural" treatments, and unfortunately charges a monthly ($15/mon) or annual fee for access.
The AARP article indicates possible interaction, especially with cardiovascular meds. The first three you list for your dad are most likely prescribed for some cardiac condition, possibly A.Fib? Just an educated guess
The AARP article also suggests consulting with a pharmacist about interactions; if you have a relationship with a pharmacist, I think this is a great idea!
Hope this helps!