DDP最常见的还是作为贸易术语，英文全称为Delivered Duty Paid，（named place of destination）中文名称为税后交货（……指定目的地）。“完税后交货（……指定目的地）”是指卖方在指定的目的地，办理完进口清关手续，将在交货运输工具上尚未卸下的货物交与买方，完成交货。卖方必须承担将货物运至指定的目的地的一切风险和费用，包括在需要办理海关手续时在目的地应交纳的任何“税费”（包括办理海关手续的责任和风险，以及交纳手续费、关税、税款和其他费用）。

但是显然跟题主遇到的语境不适用。

经过我多方查证，DDP是 “developmentally disabled person” (智能障碍者、伤残人士、老幼病残人士）的缩写。

根据美国法案 the Mental Health Code 的定义，

Developmentally disabled person/DDP means:

Under the Mental Health Code, a person with either of the following characteristics:

1) The person is older than five years of age and has a severe, chronic condition attrbutable to a mental and/or physical impairment. This condition manifested before the individual's 22nd birthday, is likely to cuntinue indefinitely, and results in substantial functional limitations in three or more areas of major life activity, including self-care, language, learning, mobility, self-direction, capacity for independent living, or economic self-sufficiency. Because of his or her condition, the person needs individually planned services that are of lifelong or entended duration.

2) The person is age five of younger and has a substantial developmental delay or a specific congenital or acquired condition with a high probability of resulting in a developmental disability as defined in 1) above if services are not provided.

【双语例句】

INDIVIDUAL PROGRAM PLAN (IPP): Under the Lanterman Act, the program plan developed by the responsible regional center, the developmentally disabled person, and the person’s parents, legal guardian, or conservator. 

根据 Lanterman Act，由负责的地区中心、发展 伤残人士、 该人的家长、合法监护人或监管人 共同制定的项目计划。