A family of 7, with 5 young childen,Father does not want to protect
his family by keeping adequate life insuance   Could another family
member do this on the childrens behalf  -- insure their dad so t

There is such a thing as "confidential life insurance" where you can
obtain insurance on someone's death without them even knowing about
it... but I don't think this is available to family members.  I have
only heard of these policies being used in business cases (ie  I have
a partner in my business... and I could not run the business without
him so I have an insurable interest on him).

The best option in such a family case is to explain to the father that
the family isn't trying to get rich off of his death, but doesn't want
to be impoverished either.  I'm assuming that the family with 5 kids
is very dependant on his income and would be put in a very difficult
situation if he was not there to provide for them.
An easy arguement to make might be enough insurance to pay off the
house you are living in (or buy a house large enough to hold the
family).  Housing is expensive yet it is a necessity whether he is
there to pay for it or not.

The life assured has to give medical details and sign to say they are
accurate.  With a larger sum assured, or medical complications then a
medical exam may be required.

Here's an example of Confidential Insurance:
http://www.piu.org/pdf/Confidential%20Life%20501.pdf