IPhone 4S sound and mic problem

So heres the thing. I got an iphone 4s for my brother last year when it came out and it worked perfect absolutely no problems. Now about 4 months ago my brother accidently fell and cracked the screen bad and the touch didn't work. I did not get any type of warranty and apple charge to much to fix so i replaced it myself by reading and watching videos before i did. And i got it installed and everything after that worked real good except the vibration but that didn't matter. Now i have no sound from the loudspeaker, the mic does not work people on the other line can't hear me, the earpiece does not work, and the headphone jack does not work. An i'm talking complete silence no sound from apps locking or keyboard sounds. And the headphone jack will work once in a blue moon but it has a weird hissing sound. I have tried to look up what's wrong but can't find a straight answer.i've had good answers on here before so i'm going to try it again

Seems like the fall has damaged the hardware of the phone

there's some kind of serious damage causing all the malfunction
the loudspeakers seem to have gone bad so the mic and the 3.5mm jack

you would better need to replace the entire set