how long would it take to do mud baths and seal approx.18 showers areas in a school im asking because my husband took a week and a half and

I don't have a personal experience with a tiling job this size, especially in a school, so I cannot answer the question of time that it takes directly. However, I do have a comment based on my experience with project management in a different trade:  two weeks is a long time, and if the productivity was crucially important to the person/company that hired him, the question of real or perceived slowness should have surfaced by the end of the first day or just about. 

The only way I would let a substantial size job to go essentially on autopilot for two weeks (I can't think of a reason I would though)  is if I completely trust the person or the team doing the job and I've already done a similar job with them, successfully, in the past. If I do trust my team, I would be open to hear their explanation of why the job has taken longer than planned and I would take their explanation seriously because it will help me estimate the next job more accurately.

If the person hiring your husband did think the job has to take one week instead of two, he should have showed up at the job site by the end of the week, at latest, and verify whether his estimation was accurate. If he was not satisfied with the speed the work progresses, he should have taken steps to correct the course and it might have even involved firing your husband at the end of the first week and finding someone who does the job faster. Or helping your husband improve the performance one way or another. But that's beside the point: doing it after the fact makes little business sense.  You can't improve performance on the job if the job has already been completed.

So, the bottom line is that if the question of slowness had only surfaced upon the completion of the job, the person hiring your husband is just trying to screw him out of half of his pay.