I'm not sure where you get your information, but you need to look it up again. First off, Needhelp999, this situation can be a little sticky, but can be won in your favor. If your girlfriend's main activities involved taking care of your home and son, and these surguries are preventing her from completing them, then they can be covered under FMLA, watching your son is actually an irrelevant detail. Now, the questions you need to answer are:
1.) Are you willing to be common law married to your girlfriend?
2.) If you answered yes to the above question. Do you meet the requirements to be common law married (you never know, you may already be considered common law married, in which case she is covered under your FMLA).
3.) Will her doctor approve your FMLA?
4.) Do you meet the requirements for FMLA participation?
If you can answer yes to all of these questions, then all you have to do is pickup an FMLA notification packet from your work, have your doctor and supervisor sign, and say bye-bye.