The only prohibitions to hunting in the State of Illinois as far as that is concerned is if you are under court order for providing child support and need to use a crossbow, or possibly not having the ability to legally possess a firearm (that isn't an "antique or replica antique" muzzleloader [aka., the standard muzzleloader]) due to the fact that you have a felony conviction. But even these restrictions can be overruled by a court order if you file a complaint against the State police and get a lawyer. A lot of Illinois residents do this. The F.O.I.D. card system is pretty much unconstitutional anyways, much like many other Illinois laws. No other State in the United States has a ID card system for firearm possession and ownership, except Illinois, which is retarded at best..... But bowhunting and trapping are 100% legal. According to "Public Act 095-0329" of the Illinois General Assembly, Effective Date: 8/21/2007, (520 ILCS 5/2.33) (from Ch. 61, par. 2.33)..."(jj) Nothing contained in this Section shall prohibit the use of bow and arrow, prohibit the use of a crossbow by persons age 62 or older, or prevent the Director from issuing permits to use a crossbow to handicapped persons as provided by administrative rule. As used herein, "handicapped persons" means those persons who have a permanent physical impairment due to injury or disease, congenital or acquired, which renders them so severely disabled as to be unable to use a conventional bow and arrow device. Permits will be issued only after the receipt of a physician's statement confirming the applicant is handicapped as defined above." ...So, as it says, "...Nothing contained in this Section shall prohibit the use of bow and arrow".

Absolutely he/she can. If the bow is of the type worn with a suit (made of fabric), or if your friend drops his/her bow while hunting, you are allowed to help look for it.

Yes, only if it is not hunting for humans.