Doxycycline gives a full recovery in 87 percent of early cases. If you have waited three weeks to take the antibiotic, you have reduced the chance that it will work for you, but there is still a good chance that it will work, so don't delay any longer. Taking an antibiotic does not make you resistant to it.
Under FMLA, an employee can take time off to care for an immediate family member with a serious health condition. The U.S. Department of Labor defines immediate family member (for FMLA purposes) as a son, daughter, spouse, or parent. Domestic partners are not spouses or relatives under the FMLA.
While no federal law requires employers to grant FMLA leave to domestic partners, companies are certainly free to give unpaid leave if they like. The ABC Company could establish a policy that they will give up to 12 weeks of unpaid leave to employees to care for in-laws or domestic partners.