A soldier who died “in Hospital”

When Ohioan James J. Vansant joined the Union Army in 1864, he was eighteen years old. He died “of disease” just months later in Alexandria, Virginia.

This soldier’s gravestone is decorated with an eagle, head bowed, a banner in his beak, perched on a flag-draped shield. Stars encircle the carving.

JAMES J.
Son of
John S. & Lucinda
VANSANT
Corporal of Co. G. 180 Reg. O.V.I.
DIED
in Hospital at Alexandria, Va.
May 1, 1865
AGED
18 Ys. 5 Mo. 3 Ds.

From Ancestry.com

What about the discrepancy between the Ancestry military record date of death and the gravestone date of death? Mar v. May could be transcription error.

Claibourne Cemetery, Union County, Ohio