Hey Guys my dads 97 Suburban4x4 is having truble

Ok does the engine turn (easely) when you start it up, if yes, then you got you're self a "crank but won't start" condition. That is a little more complicated but if it simply won't turn when you start then you got a "no crank" condition witch is preaty simple.
First be absolutely sure that you're battery is good, try an other battery on it, one that you know is good. If it starts, change you're battery. I've often seen batterys that charge but go completely dead a soon as you take the charger off of them.
Second, verify the wiring, simply inspect the cable that goes directly to the starter for a cut or damage, also don't forget to check out the engine to body ground, witch usualy corodes and cuts (it's located near the crankshaft balancer and goes directly to the boby) Repair if neaded. Also verify that you're starter relay clicks when you start. If it does not clic, then you got a burned out fuse (fuse #6 in underhood fuse block), a faulty circuit or a faulty relay (underhood fuse block)(can try an other similar relay to verify). You can also try to bypass the starter circuit by simply using a screwdriver to jump the current from the positive pole (big red wire) to the "s" pole (small purple wire) of the starter. Use caution cause sparks will fly and engine may start. If the engine starts, then you know for sure the trouble is in the control circuit.
Third, verify that you hear the starter solenoid clic when you start. Have one of you're buddys start the truck and listen for a loud and clear clic (It is realy loud) If it does not clic at all or is not loud, and all the wiring and relay is ok, then the starter may be the cause (usualy only the solenoid gives away, witch can be changed seperatly)
Good luck, hope this will help
Slant6Nova