More description needed. You said there is power, but you had to jump-start him. What are the circumstances?
Is there power if you don't jump-start him?
Does the Jeep start and then shut off while the two vehicles are still connected to the jumper cables?
If it is a bad battery (or possibly alternator), it is not unheard of to jump-start the vehicle, and then have the vehicle die as soon as you disconnect the jumper cables.
2004 Liberty Sport 3.7L A/T 4x4 Cmd-Trc
1999 TJ 4.0L I-6 4x4 5-Sp *Mods*
1986 Trooper 2.3L I-4 4x4 5-sp