California -- What is MAX INCOME for family if Child gets SSI?

When a child has SSI income from being disabled, and
the family consists of only 1 mother, child and
non-custodial parent is father, who is very helpful,
is there a MAX AMOUNT of monies per month that this
family of 2 can have income-wise before child loses
SSI?

Currently, child is disabled and very young, so mom is
attherapies all day with child and is not employed.
Child recieves SSI as income thus gets Medi-CAL.

Child needs to maintian SSI and Mother needs to maintain CalWorks
Status currently. She does not deisre the monies from the State, but
soes want the services.

Mother and Father have to this point had a goodwill relationship, and
don't want court-ordered support payments taken from his paycheck.
Court-ordered medical insurance is fine once the fahter's job allows
for this benefit. Both parents are still married to each other.

Any info wouldbe appreciated via e-mail.