Down payment for a home? How much?

My husband and I had a good amount put back for our home. Unfortunately, his mom was diagnosed with stage 3 breast cancer and she obviously had to cut back on working (she still works from home but not as much, I can't believe she does at all because she's having bad reactions to chemo and radiation) 
   Anyway, they almost lost their home so we gave them the money without any hesitation. My husband and I 100% agreed together we do not want it paid back or anything. Now we have around 3 % of what we would use. We are saving again but if we find a house we love, I'm hoping to have another 5% saved within a few months. 
  Would 10% be okay maybe? I found a house I love right now but I'm scared to put in an offer with only 3% down. We can always find another house; the money went where it was needed but I wanted opinions (: