If the adult son is the one applying for Medicaid, money received from the parents prior to the application will likely have no effect on his eligibility.
If the parent is the one applying for Medicaid and is a nursing home resident, please be advised that the Medicaid agency will investigate any transfer of assets by the parent, including gifts, that occurred in the 60 months prior to applying for Medicaid. The parent may be penalized for transferring assets without receiving "fair market value."
No, the child can not. The other parent could before the child was an adult. The money goes to the parent to use for the child and not directly to the child.
A parent can get the medical records of an adult child if the adult child gives express permission.
The only thing affecting the child's eligibility for medicaid is income and assets.
Is this a trick question? If the child is legally an adult (and therefore 'emancipated') then there is no "custodial" parent.
extremely unlikely
No. The custodial parent is/was the obligor, not the child.
No, they are not.
Only if you prove to be an "unfit" or bad parent. The parent that is an adult has not more rights to the child because they are an adult and you are not.
Only if the parent is the legal guardian of the child's person. If the child is a danger to herself or others, the parent can petition the courts for involuntary commitment.
No, the filing period ended at age 18 for the parent, and age 19 for the adult child.
No, child support is not paid to the child but to the parent raising the child.
No. What you suggest is not possible.