Thanks for your question.
You are time barred from disputing the distribution of your mother's estate to you father unfortunately, an application to dispute a person's Will must be made within 6 months of the date of the grant of probate in the deceased's estate.
You may be able to make a claim on your father's estate (when he passes away) if you can show "reasonable financial provision" and make an application within 6 months of the date of the grant of probate, .
I note you say you are not sure if your father is alive or dead. You can check to see if a grant of probate has been obtained in his estate by searching the probate calender to see if one has yet been obtained and they pay a fee to receive a copy of it (a copy of your father's Will would also be attached to it). Follow the instructions on the following site:-
If no grant has been obtained you could make a "standing search" of the calender, which will notify you and send you a copy of the grant if one is take out within 6 months of the date of the search:-
If you then decide to make a claim then you should go and see a local solicitor. He will take your instructions then write to the executors to state that you are making a claim on the estate under the Inheritance (Provision for Family & Dependants) Act 1975
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