4r44e lost all forward gears

[brownz]

Saga continues-yesterday 1 hour after his inspection he was picking up my daughter and he was in drive and he said that it lost power (slipping i guess) so he dropped it into 2 to get the 4 blocks to school and that started to slip as well. So he called and when i got there basically he had no forward gears but reverse was fine. He had been driving for 1 hour before thas happened with no problems so he says. The tranny fluid when i checked it was slightly 1/4 inch above hashed lines and when it cooled I then noticed the radiator wah low maybe a quart. My sister lives 3 blocks so we had managed to get there and into her garage. Today I thought that the tranny fluid may of been contaminated so I dropped pan and did a fluid change and ran it for 10 minutes and drained once again with filter change.While the pan was off I went and checked the valve body bolts and torqued down all were slightly loose. Started up and still nothing only time I can get any motion is to immediately after start, quickly put it in 2nd but definitely not the power it had. If this relevant or not when I met up with him yesterday the battery light was on when I went into 3,2,1 and when I put it in reverse light goes out-back on in forwards and off in reverse.
Is there anything that I can do to fix this for him or am I pretty much screwed and looking for a used tranny for it.I was going to do a valvebody gasket because of the delay in drive but is that going to solve the new issue I have. I have tried researching this but I figured I put my situation on here for the pros to check it out and get their insights. This truck took a year to give this truck a makeover and to see his first car die on him 1 hour after getting it legal is driving me nuts. So any help would be greatly appreciated.