He works as an accountant and does not pray in congregation occasionally because of that
Question

                I work as an accountant and when the time for prayer comes I cannot pray in congregation sometimes, until my colleague comes and replaces me. Please note that outside of work I offer all the prayers regularly in the mosque.
Praise be to Allah.Prayer in congregation is 
    obligatory for men who are able to do it, according to the more correct of 
    the two scholarly opinions, based on a great deal of evidence that has been 
    explained in the answer to question no.
    8918. 
An exception from that is 
    made for the one whose work cannot be left because obvious harm would result 
    from that, such as those who guard important places or doctors doing surgery 
    and the like; they may stay away from prayer in congregation. 
As for working as an 
    accountant, there does not seem to be any reason for not praying in 
    congregation because of it, because you can close the books, computers and 
    offices in order to go and pray. The boss has no right to stop employees 
    from praying in congregation. This has been discussed in the answer to 
    question no. 72895. 
We advise you to try to 
    pray in congregation and to do things that will help you to do that, and to 
    advise your bosses at work, because prayer is the most important pillar of 
    Islam after the Shahaadatayn, and it is the cause of success and prosperity 
    in this world and in the Hereafter. 
And Allaah knows best.