transferred his shares

Dear Sir,

My grandfather passed away three years ago. He had businesses in the form of two private limited companies. During his lifetime, he transferred his shares in the business to my Aunt and Uncle only. My father who was the remaining child received no share in the business. On his death, the businesses were in the name of my Aunt, Uncle and my grandmother.

Please advise if there is anything that can be done against this injustice with my father. My father is a bit slow from early childhood as he caught menangitis when he was an infant. So he could not find out sooner and they took advantage of this by cutting him out.

Please tell me is there anything that can be done? Anxiously waiting for your reply