I have a shomer shabbos family in my neighborhood that are entitled to have social therapy services from the city for their son. They are entitled also to have hours on Shabbos afternoon as well. There is a possibility that I can be the one providing these services for their son. I would be getting paid by an agency and I would have to perform those services during the week and on shabbos. No chillul shabbos is involved. Would I be aloud to do this, and if so, is there anything I should do in terms of the payment arrangements or anything else?
As long as you are being paid a salary for all your time together, you can do this work on Shabbos.
It is generally forbidden to take payment for work performed on Shabbos. In your case there are a number of reasons for leniency. Firstly, your work is during the week as well. As long as the pay is for the entire work this is knows as “havlaah”, when the Shabbos pay is as part of salary for work during the week as well. In addition this may be considered medical care for which one is allowed to receive payment. See Shulchan Aruch O:C 306:4, MIshna Brura ibid. 24, Minchas Shabbos 90:19