AITAH for never disclosing to my grandchildren’s father how much I planned to give my grandchildren toward their futures?

My daughter died when my two grandchildren were young. My son in-law remarried and created a blended family of his/hers/theirs. My husband and I knew our daughter had left some money in a trust for our grandchildren's future. But she was young when she died and didn't have a lot to leave them. So we decided to make sure they would receive a very comfortable amount from us once they reached 18. This was to help with college, or pay for a house, or to allow them the ability to train for their dream careers.

We never told our son in-law. This was done so we would not be asked to split the money between all the children and so our grandchildren would not be prioritized less by their father or his wife. This money was not supposed to act as child support or money for the household. It's for my grandchildren.

Our oldest grandchild graduated two years ago and we gave her access to the money and she never told her dad. Our youngest grandchild graduated this year and was quick to set up a high interest savings account and he made the choice to skip college to pursue a different path toward his career. This led to a conversation where my son in-law learned about the savings.

My son in-law's wife was furious with my husband and myself for not disclosing the money to them years before. My son in-law was hurt we chose to do this instead of giving something to all the children. He said us not telling him added to his hurt because he had hoped we would want all the children to have the same start in their adult lives. He felt like we should have told him so he and his wife could plan accordingly.

My youngest grandchild moved in with us after the trouble started and both my grandchildren have discussed the issue with their dad several times. But he still insists my husband and I should have told him.

AITAH?