I know the feeling Dawn sadly there are many of these
about . Sometimes tho you have to remind yourself that you can't save everyone so essentially don't sacrifice your time for the needy to chasing up after this
So long as the cats are safe and loved give them advice and if they are willing to meet some of the cost of the neutering then great... see if you can get them CP vouchers or just make part payment.
I know its not an ideal scenario but for someone like yourself working on your own essentially with other committments you have to way up the pros and cons.
Let us know how you get on tho... fingers crossed for you hun!!!