The short answer is, probably not.
The longer answer is, to claim your daughter as a dependent, she must have less than $4700 of taxable income, AND you provide more than half her total financial support (not just housing, although that counts), AND she does not file a joint tax return with her spouse.
Or, you can claim your daughter as a dependent if she is permanently disabled and unable to perform gainful work, AND she lives in your home more than half the year, AND she does not file a joint return with her spouse.
To claim your son-in-law as a dependent, he must have less than $4700 of taxable income, AND you provide more than half his total financial support (not just housing, although that counts), AND he does not file a joint tax return with his spouse.
To claim your grandchildren as dependents, they must live in your home more than half the year, AND you (and your spouse, if married) report more taxable income than the parents, AND you also meet at least one other condition, either,
a. the parents agree not to claim the children as dependents, or
b. both parents qualify as your dependents (because if the parents qualify as your dependents, they are not allowed to claim their own dependents even if they wanted to).
