Linda, again, you need to do more research on your car to determine ANYthing...
For instance, the air blowing weakly HAS NOTHING TO DO WITH THE COMPRESSOR HE PUT ON....
I can see that you would be upset by his actions..... but that is different from making the jump from the physical indicators which you have listed so far... to him putting either a bad compressor in.. or the ac work in general not currently working...
You will have to check out the CONTROL parts of the system... he has no way to tell when the other stuff is going to go out... but it can affect the impression you have of his work.... but it is not fair to do it that way....