Hi,
There are no Income Tax implications on the receipt of a cash gift unless the cash gift generates interest or dividends. These would then potentially be subject to tax. You can see guidance here:
Tax on savings interest
Tax on dividends
As you are keeping the income in Spain, you would declare any interest, and, or dividends as foreign income.
For the property, you will only pay tax if you are receiving an income from it or when you sell it.
Thank you.