Do you happen to like the same kind of coffee that your Mom and Dad enjoy? That would help somewhat as you could enjoy a cup here and there and make a decision based on the best you find. I am am somewhat of a coffee snob, although have resisted developing a taste for the high-priced stuff.... and it can get really, really pricey, believe me! I am also a sucker for things with a Mickey label.
Much to my delight, I found that the bagged coffee sold as Mickey's coffee or similar, is a very pleasant brew. Not Kona, or Blue Mountain for sure, but definitely drinkable to me. It is not a terrible price as coffee of souvenirs go, either. I have also bought the little gift packs of cutesy-pie miniature containers that offer a variety of flavours. I don't care for flavoured coffee myself, but I break up the set and set them on the desks of my closest co-workers to let them know I was thinking of them. I keep the unflavoured one for myself and enjoy it. Maybe the packaging helps the taste, psychologically. I just know I drink it with a smile and hopefully your mom and dad will do the same.
Ps - if they really hate the coffee, the grounds are great in a garden, for certain plants. Always a silver lining.
Happy coffee hunting!