Death and a will left behind...?

My Father has a will from his Brother, (my Uncle). The only known will he had, states that everything he had, is to go to my Dad. He was then married, for 6 years. My Uncle ped away 2 years ago. His wife now has everything that was supposed to be left for my Dad. All of my Uncles belongings were in his will prior to marriage and now she will not give anything up. All the items I am referring to were family heirlooms. They need to remain in the family, not hers. She is re-marrying this week and I need to know if I have a case to get my Father the things that my Uncle left behind. Where would I even begin to speak with someone about this? I live in California. If I may be more clear: The will was created one year prior to my Uncle marrying her. They were married for 6 yrs. He ped away. She now says that since they were married after the will, that the will is now void. Well, I think that may be true to an extent. However, most items I am speaking of were the ones stated in my Uncle's will to be left to my Father. Does a marriage automatically void any prior will? This is all so confusing but were talking about items that have been in my familly for over 60-70 years. Handed down from my great-grandfather. The reason we have waited this long to bring this up is because we wanted the intial grieving process to subside before speaking of materialistic items. However, now she is re-marrying out of nowhere and this new man will now gain full access to these items. I also am doing this for my Father- meaning: I am not going to take the will in myself; just asking this question to know where I may lead him in the right direction. Thanks so much!