Your kid's spouse can't have them if you spell the limitation in the trust.
Be carefull on gift tax - If your child/grandchild has no financial ability, you can't simply add their name on your property title without tax sequence.
If you are very sure that xx million will be given to your child/grandchild, you may buy life insurance and have the child/grandchild as beneficiary. After the policy owner passes away, the beneficiary gets proceeds 100% tax free. Also,you reserve the right to change the beneficiary; and you may either sell the contract if you change your mind or use the money before you go away if you are classified "to die soon" :>)
