Is it lawful for a company to fire my husband while I'm still in cancer treatment ?

Regardless of whether your husband works for the government directly or for a private company, there's nothing in your post that immediately indicates there's anything illegal going on. Employment positions with the government are afforded certain due process before an individual can be fired, while private companies don't necessarily provide such rights, but either way the health care situation of a spouse is generally immaterial to one's employment status. You don't indicate *why *your husband is on administrative leave, which is a key consideration. If he's in the process of being fired *because *you're receiving expensive health care treatment under the group plan, then you might have a viable claim. If there is no causal connection between his firing and your health care status, however, and the two are merely incidentally connected and effected, then there's likely no legal claim. In short, yes, a company can fire him while you are still in treatment. Whether or not the company is legally doing so in this particular instance, however, is hard to say without more information. Additionally, if your husband is fired, he should look into getting COBRA benefits, which can continue to provide health care coverage for some 18 months after termination.