Sorry to read that you were on the sick list.

This is the most recent information from the US Department of Veterans Affairs regarding headstones. You can get the required form from the website.

Regardless of the date of death, VA will furnish, at no charge to the applicant, a Government headstone or marker for the unmarked grave of any eligible veteran in any cemetery around the world. There is NO charge for the headstone or marker itself, however arrangements for placing it in a private cemetery are the applicant’s responsibility and all setting fees are at private expense.