Well it seems like Hallowed and CB pretty much answered your questions.
about the person saying
How is he NOT planning his finances? Trying to figure something like this 6 months ahead of time is better than 95% of people.
That being said JF, I'd make sure I considered if she's going to need this place as a reference. If I told someone that them working for my business was contingent upon then working the summer, and they quit right before the summer, I personally wouldn't feel obligated to give them a good reference.
Also, I'd consider the economic situation of wherever you're living as well. If it won't be easy for her to find another job....then 3 months without pay is better than 6-9. If it's at all possible, if she doesn't have another job lined up, I'd just try and tighten the budget or push back the house purchase for a couple months.
Furthermore, will you be able to get a house loan for the two of you with only you being employed? This seems pretty important.
I'm just a 20 year old who's interested in finances, but just some food for thought.
Edit: Just saw that she might not be able to/want to return to the job. I'd start job hunting now.