这里应该用这样的表达
find sustenance in sb/sth
或
find resources in sb/sth
父母长从子女身上寻到精神寄托
Parents are always finding sustenance in there children.
在口语中
常用one's meat and drink表示精神寄托,但此处不适合
例：
To some old people,raising pets is their meat and drink.
对于一些老年人来讲,养宠物是他们的精神寄托