we can not give legal advice about whether it was a gift or a loan. there is a big difference. if you did return the money with interest, the interest would not be deductible. any gain on the sale of your home would be taxable to the extent it exceeded any available exclusion. married couples filing a joint return can exclude up to $500.000 of the gain under the following conditions:
1) either or both of you have must have owned the residence for at least two years out of the five years prior to the sale and
2) both of you must have used the residence as their principal residence for at least two out of the five years prior to the sale (if only one meets this condition and the other condition above is met the exclusion is $250,000) and
3) during the two-year period ending on the date of the sale, neither spouse excluded gain from the sale of another home (there is a special rule if this condition is not met by one of the spouses)
