Get her something, whether its homemade or storebought, but don't leave her out or just stick somethign in your son's stocking. Last night was our Sinterklaas celebration with DF's family. Everyone gets a gift and writes a poem for another person (we draw names). I was the only person who did not get a poem and whose gift was (obviously) NOWHERE near the set limit for gifts (ofc I understand that saying "no more than 25 euros" doesnt mean you have to spend 25, but getting a present that cost less than 5 and was completely generic when you spent so much time and effort on your gift and poem stings).
DF's mom brushed it off, saying that DF's grandma didn't know what to write, but it was pretty hurtful that after 18 months of knowing each other, she couldn't jot down even 2 lines for me to read aloud (its a BIG part of the holiday) and I couldn't help but feel that if it had been a "real" family member, she would have tried harder or someone else would have written something to make up for it. A lot of the people had 2 or 3 poems written to them and I just had to sit there. It really makes you feel left out.
I got over it (ok, I WILL get over it. It was just last night
) but I will never spend the amount of effort that I did this year (over a week building this intricate huge paper mache perfume bottle and almost a month working on writing a poem completely in Dutch) again.