Iphone *4S* in recovery loop able to toggle dfu but WILL NOT restore....

I APPOLOGIZE THAT THIS POSTED QUESTION OF MINE IS SO LONG. HOWEVER, IT IS A NEED TO KNOW BASIS FOR YOU ALL IN ORDER TO ASSIST/HELP ME WITH THIS MATTER THANK YOU FOR READING.... First of all i highly appreciate all of you taking time to read this question as well as all of your efforts to assist me in this matter thank you.... Here is the issue.... My 15 year old brother purchased an iphone 4s from ebay at $75.00. The description and status of this iphone 4s stated that it is "STUCK IN DFU MODE" we knew nothing about the dfu situation. (or how highly difficult it would later be) So he asks me if he should buy it, well i said yes thinking that this problem sounded legitament as well as easy/simple to bypass and or repair. Therefore he purchased it thinking we could bypass this dfu problem, and he would finally have a fully functional iphone 4s as he has been anticipating to own one. As He knows more about idevices than i do and owns alot of them from ipod touch all the way up to this stubborn iphone 4s. He began to work on this iphone 4s project trying to get it to boot up and work correctly for a couple of days, and hours at a time, it wouldnt no matter what. I then took over the project, and i have to say, this particular iphone 4s, is very corrupted/damaged as far as something software/firmware related within this iphone 4s. So for several hours at a time for almost 3 or 4 months into this grueling project this morning included i have been putting all of my effort into fxing this iphone 4s. I couldnt/cannot get it to restore on itunes (of which we both have the most recent update of itunes) in recovery mode and in dfu mode. I toggled our firewalls to allow the itunes update server. I as well as i toggled our anti-virus programs into disabled mode for the times of which we have been trying to restore and update this iphone. It did update, however, as usual it will not restore with itunes it *ALWAYS* responds back to us with itunes the cannot restore this iphone, the following unknown error has occurred,error (9). I then proceeded to searching online for a solution to the problem(s). As well as this error code (9) itunes continuosly states, After it shows a loading bar under the white apple logo/boot screen on the iphone 4s. It soon there after tries to restore it then responds back with the afformentioned error code (9). The thing is that ive researched, researched, and researched on youtube, bing, and other forums. As i did not know about this apple support community until this morning. Ive spent about 2 and a half hours searching the community here. So yes, i have searched the support community thoroughly. However i have yet to find the solution to the iphone 4s errors we are facing with this potentially irreparable iphone 4s. I am in great hopes that it cant be completely useless, static shocked, or "bricked" because it turns on and registers on itunes etc. Ive went so far as opening the iphone 4s as well so as to see if it would happen to be a hardware issue. Yet everything on the inside of this iphone 4s, is in perfect order as well as new just as the outer casing and the screen. he ordered this iphone 4s from some seller profile of which was a cell phone store/seller (or so it said) on ebay. So my thoughts on it now are if they couldnt get this iphone 4s to boot up and fully function. Then im not sure if i can either, as i know nothing about idevices period. However i have learned a whole lot about them now. in conclusion all i can say about this entire situation with my brothers iphone 4s is that, i hope that i can get it repaired by myself with the proper assistance through the community from you all... 🙂 But right now i feel sad for my younger brother because i cant seem to get his iphone up and running of which he is excited to have working and he is relying on me to get it fixed....

P.S.- I think that this iphone 4s has probably been dropped and something inside is loose causing it to have all of the issues it is having im not to sure though.... its just a thought i had about this iphone, also maybe it got too hot and it is therefore malfunctioning? and if that is the case then theres got to be some way to fix the hardware inside of this iphone by soldering or just simply unplugging something and then plugging it back in? again these are just some thoughts ive had about this whole situation. I mainly think, that this iphone 4s somewhere along the lines, was corrupted/damaged by the person(s) who has had it/owned it in the past. They had to of tampered with the iphone 4s by jailbreaking it or attempting to do so. Or they may have damaged it by improperly updating the ios, improperly attempting to restore it, or downgrade it, etc. And the only "SOLUTIONS" i found online, were various programs to fix all of the problems/problemthis iphone is having trouble with. NOTE: these programs i knew absolutely nothing about or how to use them. Only by following youtube tutorials etc. i eventually learned my way around them. Anyway EVERY LAST ONE OF THESE PROGRAMS FAILED VERY MISERABLY in repairing this iphone 4s. I found all of the following programs and attempted to use all of them with my brothers iphone 4s they are all up to date and are as follows: redsn0w, ifaith, tinyumbrella, ireb r7, sn0wbreeze, bluefreeze and recboot. these were all reffered to me by youtube and other forums to "help" with an iphone 4s. i do not know anything about these programs as far as if i should have used them. However, like i said they were on youtube and such so i got them in a desperate attempt to fix my brothers iphone 4s and again i appologize this posted question of mine was very long however majority of this information is a need to know basis in order to help/ assist me in this matter THANK YOU ALL....