Legal Question in Wills and Trusts in Massachusetts

You can challenge the Will but will need to demonstrate undo influence, mistake et cetera. A child has no right to inherit from a parents estate.

I am going to assume your father passed away. As a caregiver, if your father promised you something in exchange for taking care of him for 7+ years you can make a claim against his estate for what was promised to you or reasonable compensation from the estate.

You do not say when the Will was created or who arranged for the Will to be drafted. If your brother took him to an attorney to prepare and sign the Will you may have a good basis to assert undue influence or fraud.

More facts are required to determine the quality of your case and you should meet with a lawyer to determine the quality and value of your case. An initial meeting is generally free.

I will tell you in advance Will contests are expensive.

You did not say your father has died, which I assume is the case, if he has not passed then I would suggest you ask him to execute a new Will assuming he is competent.