Economic stimulus payment?

I need to know if the following scenario will qualify for the tax rebate. Elderly married couple (both in their eighties), He lives in a nursing home in Wisconsin, receives SS, medicaid, and a small pension ($6500 per year) from GMC. She receives only SS. and lives in their Wisconsin home. They do not normaly file an income tax return. I know she will qualify for the rebate but what about him because of the fact he receives medicaid? If he is eligble, Should they file Married jointly or married seperately?