38 C.F.R. § 3.455
Apportionment of a surviving spouse's dependency and indemnity compensation
(a) Conditions under which apportionment may be made. The surviving spouse's award of dependency and indemnity compensation (DIC) will be apportioned where there is a child under 18 years of age and the surviving spouse is incarcerated and meets the provisions of § 3.665. DIC will not be apportioned under this paragraph (a) for a child over age 18 years unless the child is permanently incapable of self-support in accordance with the provisions of § 3.57.
(b) Rates payable. The amount of apportionment of DIC will be determined in accordance with the provisions of § 3.665.