Can I use maser money to buy my grandchild tefillin. My son is jobless for awhile and low on funds generally. I know for a child its questionable. How about a grandson. Thank you
You are not obligated to buy your grandchild tefillin, therefore you may use maaser money for it. In fact it is a very high level of tzedakah, because it is for a relative.
Shevet Halevi 5-133, B’orach Tzedakah 11-97.