Dear Sir,
1. You can gift the money to your daughter's son. No issues.
2.No gift tax involved.
3. It's always better to execute a gift deed. If you can't execute registered gift deed at least have it documented on the stamp paper. (We can help you in drafting gift deed)
Please note that recepient of gift need to show the amount in ITR.
Please feel free to call/revert in case of any doubts
Thanks and Regards
Abhishek Dugar
CA CS B.Com