no
No
Is this a trick question? If the child is legally an adult (and therefore 'emancipated') then there is no "custodial" parent.
your parent's are legally responsible for you until you turn 21; so technically, you are not legally an adult until you turn 21.
No, a mentally incompetent adult cannot be charged with parent elder abuse, but, they must see a doctor; tested for their mental incompetence and absolved of looking after their elderly parent.
Legally you are not. Becoming a parent wont change that.
The residence is the property of the parent's - you have no legal "standing" to continue to occupy their residence. the law only requires that your parents support you and be responsible for you until you legally become an adult. Once you become an adult you become a resident of their domicile at their "sufferance." and you can be invited to 'quit the premises' at any time.
It is generally the adult children of the elderly person that tries to get their parent into a nursing home if the elderly person is no longer competent to look after themselves, but in many States and in Canada this has to be doctor approved for the security of that elderly parent because some elderly parents are quite capable of living with their grown children or even on their own. However, either in a Will or if the elderly person is lucid (thinking very clearly) they can name anyone to become Power of Attorney to care for them if they do not trust their adult children's decisions.
Only if the minor has legally been "emancipated" by action of the courts.
If the child is 18 or older, and is not in custodial care of the parent by the courts, they're legally an adult, and the parent has no legal right to lay claim to their tax returns.
In the state of Texas a person becomes legally designated an adult at the age of 18. In most cases the parent(s) will no longer be legally or financially responsible for the child (an exception could be a child support order that stipulates a different age). If the parents so choose they may request their "adult" child to move from their residence.
At the same age in every other state in the U.S.A - 18 or when the parent legally grants EMANCIPATION to the minor in question, which requires the adult to petition a judge for the release the child from their responsibility.
In the US at age 18, you are legally an adult, and do not require permission of a parent for most things.