05 jeep liberty 3.7

2005 Jeep Liberty
Working on friends jeep she had battery light come on and started heading home about 30min 25miles later overheated and stalled.. i went the next day and pulley was loose replaced water pump and coolant started car and it was jerking running rough.     Pulled codes p0300(multiple misfire) P0700(transmission control module malfunction) and p0562 (system voltage low).   I replaced the spark plugs and battery still ran rough at idle but ok going down the street almost stalls between drive and reverse and at stops.  only took out to refresh codes since battery disconnect.   New codes are P2305(cylinder2 misfire) p2311 (coil 2nd circuit number4 cylinder) and p0123(TPS detects high volts…   now i had pulled all the coils once and,checked the tps when i was diagnosing looking for any heat damage and also to see which coils were not affecting when unplugged.   I cleared codes and all im getting now is p0175 p0173 which is rich exhaust detected by o2 sensors but the three it just showed weren’t there anymore… now she ordered 2 coils and a TPS and went to a mechanic who tells her its blown up wont be specific at all he claims its got no oil in it however i checked the levels and they were fine before i left it parked there without TPS or the two bad coils in it so she couldn’t drive it how could it be blown also how could it not be blown because I’m no certified mechanic but i know a lot and i didn’t think it was blown up beyond repair it was still starting, and idling before i removed those parts..? Suggestions opinions help?!?!