Your doctor can give his opinion on whether she/he believes you are disabled and eligible for DIB, but this is not decisive. Your doctor’s opinion must be supported by his/her treatment records of you. The opinion must be consistent with the other medical records found in your file.
Doctors often write: “I believe this person is permanently disabled.” While this sounds good, it really does not help in a Social Security Disability case.
Doctors help their clients the most by discussing why your problems render you disabled; what kind of physical and mental restrictions you have from your health issues and what type of treatments you have tried. If your doctor says you are disabled, it may help your DIB case, but only if it is properly supported by the rest of the medical records.