VA disability benefits are available for any person who served on full-time active duty. There are also other categories that apply. A veteran, dependent or survivor is eligible for disability benefits if they can tie a death or disease to a period of active duty for training—such as when a reservist is on orders for an event like basic training, or schooling for an MOS.
VA also considers inactive duty for training periods eligible if a person was disabled or died from an injury occurring or aggravated in the line of duty. Such examples from the case law include a reservist hit by lighting during drill weekend. This definition also appears to mean, under the right circumstances, that a reservist who is severely injured in a car accident on their way home from drill weekend may be eligible.