The US citizen can sponsor his wife for a green card, not for US citizenship. Since he is currently unemployed, he will need to get a joint sponsor to complete an affidavit of support for his wife.
Yes
Yes, but the US citizen should sponsor his/her spouse's immigration in order for him/her to get a green card.
i will marred
YES
No, just the child.
A non-citzen can become a citizen in the US if they follow the proper procedures.
Vote.
No, its no mandatory. but its just that if your a citizen, you can vote, easier to travel outside the US, and sponsor relatives to come to USA.
A citizen can petition their parents if the citizen is at least 21.
You cannot sponsor someone who is already here illegally. You CAN sponsor them if they go home and apply for entry with a sponsor who will provide a home and/or a job.
obviously not