If you have time for amendments 15 April, I'll hire you to prepare returns for me!
Wait to file until client has made a decision. Give client a DRAFT return to give to bank.
If he owes 15K and can't pay it now, how will he buy a house and pay closing costs, homeowner's insurance, repairs, moving expenses, etc. Maybe he should invest in his IRA instead of a house. Or, maybe he should invest in a house instead of an IRA. But with a 15K tax bill, can he afford both?