A Father-in law is considered closely related; so there is no requirement that he lived with the taxpayer, at any time.
From Pub 501:
Member of Household or Relationship Test
To meet this test, a person must either:
1. Live with you all year as a member of your household, or
2. Be related to you in one of the ways listed under Relatives who don't have to live with you.
.
Relatives who don't have to live with you. A person related to you in any of the following ways doesn't have to live with you all year as a member of your household to meet this test:
• Your son-in-law, daughter-in-law, father-in-law, mother-in-law, brother-in-law,
or sister-in-law.
Any of these relationships that were established by marriage aren't ended by death or divorce.
______________________________________________________________________________________________________
An in-law is closely related so there is no requirement that he live with you at any time, during the year. But if you provided a home it helps your support case, unless they own the home you live in. If no one person (or married couple) provides 50% of the support (for example your siblings are also sending support), then a "multiple support agreement” (IRS Form 2120) can be used, to allow you to claim the dependent. <a rel="nofollow" target="_blank" href="
https://www.irs.gov/pub/irs-pdf/f2120.pdf">https://www.irs.gov/pub/irs-pdf/f2120.pdf</a>
The IRS has a worksheet that can be used to help with the support calculation. See: <a rel="nofollow" target="_blank" href="
http://apps.irs.gov/app/vita/content/globalmedia/teacher/worksheet_for_determining_support_4012.pdf"...> The support value of a home is the fair market rental value, divided by the number of occupants.
