My first thought is that rather than starting
an independent foundation, which requires lots
of overhead, that you perhaps first propose being
a program affiliated with a larger organization.
For instance, there must be groups that exist
to support mentally ill adults and perhaps even
more specifically mentally ill parents. I would
start by reaching out to these groups about partnering.
A model for this is both AIDS organizations as
well as gay and lesbian organizations — both
of these organizations exist and then have a
subset of programs such as children of parents
with AIDS or parents of gay and lesbian children.
Also, the AA model is like that with the offshoot
for family members of alcoholics. Another route
might be going via groups that are specifically
working with children and partnering that subset.
If all of that fails, you should start out on
your own. I would first get together a mission
and vision — what type of support will
you provide (in person group meetings, resources,
housing, etc.) and to whom will you provide (locally,
nationally, internationally) and how (via an
office, the Internet, etc.). Once you can be
more precise about what you want to do and how,
you might find a lawyer to help you establish
a non-profit organization. Once you have done
this you can start raising money for your work
and also start doing your work. That seems many
steps away. And once you have that done, you
will need to get the word out — likely
to the groups mentioned above.