Sentence:  Finally , whatever the techniques used , a twin goal is common to all preventive casework service : to cushion or reduce the force of the stress impact while at the same time to encourage and support family members to mobilize and <WSD>use</WSD> their ego capacities . 
Meaning of the word marked with <WSD> tags:  put into service; make work or employ for a particular purpose or for its inherent or natural purpose