True, the intentions behind the giving or thought of giving is actually the main thing in giving.
Just as the saying goes,

' The intention behind our giving and receiving is the most important thing. When the act of giving is joyful, when it is unconditional and from the heart, then the energy behind the giving increases many times over.' - Deepak Chopra

Am sure you really wanted to spoil your mum(we all do), but her having this knowledge is(I use 'is' because she lives on) most priceless to her.