When deciding custody, the Judge is always going to do what is in the best interest of the child
. The Illinois section which I have provided below, states what the Judge is going to consider and what he will need to show, as the moving party. At the trial, you and your witness are going to want to show that is it NOT in the best interest of the child for your ex to be awarded sole custody. To do this, you will want to show that custody should continue to be shared, that he is not fit to solely care for the child and that you can meet the factors stated below, just as well as he can. Your witness should testify to things which he/she has first hand knowledge about, to either support your position or to discredit his.
(750 ILCS 5/602) (from Ch. 40, par. 602)
Sec. 602. Best Interest of Child.
(a) The court shall determine custody in accordance with the best interest of the child. The court shall consider all relevant factors including:
(1) the wishes of the child's parent or parents as to
(2) the wishes of the child as to his custodian;
(3) the interaction and interrelationship of the
child with his parent or parents, his siblings and any other person who may significantly affect the child's best interest;
(4) the child's adjustment to his home, school and
(5) the mental and physical health of all individuals
(6) the physical violence or threat of physical
violence by the child's potential custodian, whether directed against the child or directed against another person;
(7) the occurrence of ongoing or repeated abuse as
defined in Section 103 of the Illinois Domestic Violence
Act of 1986, whether directed against the child or directed against another person;
(8) the willingness and ability of each parent to
facilitate and encourage a close and continuing relationship between the other parent and the child;
(9) whether one of the parents is a sex offender; and
(10) the terms of a parent's military family-care
plan that a parent must complete before deployment if a parent is a member of the United States Armed Forces who is being deployed.
In the case of a custody proceeding in which a stepparent has standing under Section 601, it is presumed to be in the best interest of the minor child that the natural parent have the custody of the minor child unless the presumption is rebutted by the stepparent.
(b) The court shall not consider conduct of a present or proposed custodian that does not affect his relationship to the child.
(c) Unless the court finds the occurrence of ongoing abuse as defined in Section 103 of the Illinois Domestic Violence Act of 1986, the court shall presume that the maximum involvement and cooperation of both parents regarding the physical, mental, moral, and emotional well-being of their child is in the best interest of the child. There shall be no presumption in favor of or against joint custody.
(Source: P.A. 95-331, eff. 8-21-07; 96-676, eff. 1-1-10.)