On preview, I noticed your response, and I understand where you’re coming from. You don’t have to justify your finances, and, in my opinion, you are doing the right thing with the plan you have laid out. It’s just that the school is not going to see it that way.
Talk to an accountant or attorney about making the money untouchable or otherwise unable to be considered as part of a financial aid application.
Fair enough. But, you do realize that there are people who can’t pay the tuition and have no assets? Resources are limited, which is why you are even confronting this problem.
If you’re looking at private donations (from local organizations, charities, etc), then explain the situation, see what happens.
But, if you’re trying to get money from the school (in the form of need-based scholarships) that would go to another student without your means, then I’d suggest you look for funding elsewhere.
After all, there is an alternative. Perhaps one you won’t consider, but you’re talking about private school tuition. Why is public school not an option?
What about merit-based aid? Looked into that at all?
I AM a financial aid officer, and I’ll just ignore the vitriol directed at my profession in this thread, because I know all of us Dopers try to be open- and fair-minded…mind you, I work at a university but I imagine at least some of my experience might be applicable.
When a parent or student contacts me wanting to know if I can exclude large assets from their aid calculation, my answer is an unequivical “Maybe” 
In your case, I’d say provide a detailed letter to the school, explaining just what you’ve told us. Emphasize that this “chunk o’change” is for the purchase of a new primary residence, rather than money you’re going to use to buy, say, a vacation home or rental property, if that’s the case. Then simply ask them what, if any, documentation they would like for you to provide along with your appeal letter. I’m not saying they’ll approve your appeal but this is probably the bset way to begin approaching the situation. Each institution will have their own guidelines, depending on their level of funding, but I’ll just say I have approved an appeal similar to yours, although only once in the last 9 years. Good luck!
One of these things is not like the others, one of these things does not belong . . . .
Thread closed per request of OP.