Even at your father's age the cae has significant value (assuming good liability) - five to six figures -but I doubt you will get it from an insurance carrier pre-suit. They will offer you minimal money and string you along and hope your father dies before his testimony is preserved. You should consider hiring a lawyer who may want to put the case into suit ASAP so your father can be deposed and his testimony preserved. Without his testimony you may not have a case.
.28 is really high. You face up to 4 years in jail. Whether you actually get jail may depend on what County your case is in. I suggest that you look for a criminal defense lawyer who can paint you in a very good light to the DA and Judge.
Read your school documents to see if you are obliged to report arrests. You probably are not. A misdemeanor conviction would not automatically prevent you from becoming a lawyer. I suggest you retain a good criminal defense lawyer who knows how to handle a dwi case and consider getting into an out patient program.
The lawyer will go over each area that needs to be addressed in the will and then draft it. The lawyer needs basic information from the client such as how the client wants assets distibruted, who the Executor(s) will be, who will raise the kids if there are kids, etc.