Grandpa’s and Grandma’s stocks. Please Help.

So I was so close to my grandmother and when she passed she said don't forget tell your dad about all grampys stocks that she never touched. So both grandparents have passed and my father is very ill is there anyway we can get these lost stocks there are 100s of old stocks from Bell at&t and all old stocks from the 40s-60s I believe and it's alot of money. My grandparents only had 2 kids my dad and his brother both don't want the stocks they want us kids to get them if ever possible.