Sim,
Welcome to the forums.
There are a number of options available to you.
Please feel free to ask qestions but please do use the search facility located at the bottom of page first to see if answers to frequently asked questions are already available.
In this case a search should return a number of the options so you can look through them and see if one is more suitable than another for your needs. Perhaps that would be most helpful as I dont know what your knowledge or skill level is if you are new to game making.
If you cant find a solution or need further help then I am sure as said others will answer directly in more detail here how you can achieve what you want.
A future update for FPSC may hopefully provide for a simple option to turn the blood off, but I cant say that to be the case.
I look forward to seeing you and perhaps you son here more often.
There is a lot of help availble here if you need further assistance.
Quake is good.