Your husband could be required to comply with the employer's vacation day policy. That means, for example, that if he failed to get prior approval for the days or schedule them in advance, he might not be able to after-the-fact use his vacation days to cover his absence; if that's the case, his absence would be unapproved or unauthorized, and he could be terminated for it. So the first question is whether your husband used vacation days properly, in accordance with company policy and/or supervisor approval.Even if he did not have the right to use his vacation days to cover for this absence, if he would have been eligible to take Family and Medical Leave Act leave (FMLA) and asked to take such leave, he could not be fired for taking it. To have this as an option, the employer would have to have at leat 50 employees; your husband must have worked for them for at least 12 months and to have worked at least 1,250 hours in the last 12 months; and your condition (which he stayed home to help with) must have been serious enough to qualify under FMLA; you can find more information about that at the Department of Labor website, under "Family and Medical Leave Act." Note though that even if you would be coverd under FMLA, you have to specifically request FMLA leave...you can't necessarily or always take leave without permission, then try to retroactively make it fit under FMLA, though it would certainly be worthwhile trying that if you needed to.On the other hand, even if he properly used vacation days and/or FMLA leave, if your husband lied to the employer about where  he was or why he needed days off, that could itself provide grounds to terminate him--employers may terminate employees to lie to them.In short, there is no simple answer to your question--it depends on the circumstances. If your husband has been terminated, it would be worthwhile for you and he to meet with an employment law attorney to discuss the matter in detail.