The result depends on whether your grandfather left a will instructing what would happen if one of his children predecessed him whether the estate passed by intestacy. Under the second scenario you would inherit but possibly not under the first. Consult with a probate attorney to determine if the distribution was correct.
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Attorney Reed is absolutely correct. You need to see Grandpa's will to obtain the answers to your questions. Then seelittle competent counsel to explore your options.
My answer is not intended to be giving legal advice and this topic can be a complex area where the advice of a licensed attorney in your State should be obtained.
All any of the lawyers here can do is speculate without seeing the documents. I speculate that your mother became an owner upon your grandfather's death. When she passed she left her estate to her husband, and that's how he got the check. But I am speculating. I agree with the other attorneys, take your documents to a lawyer so she can read them and give you the correct answer.
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Since there are differences, state to state, in Probate laws, you may want to repost in PA so that a lawyer that is versed in that law can respond.
Carol Johnson Law Firm, P.A. : (727) 647-6645 : firstname.lastname@example.org : Wills, Trusts, Real Property, Probate, Special Needs: Information provided here is anecdotal and should not be relied upon or considered legal advice. Every matter is different and answers given here are general in nature and may not reflect current Florida law at the time you are reading this posting. Please contact me if you feel you need additional assistance with your matter.