Since dad lives with me can I deduct any expenses?

Rosses, the vast majority of grown children who are caregivers for their parent(s) are not paid.... unless the parent can pay from their own savings account.

Since your Mom is not a U.S. citizen, then Medicaid is totally out of the question. You may want to check with the government where your Mom lives to see what is available for her.

$1400 a month is not SSI (Supplemental Security Income). For 2018 that max is $750. SSI is not Social Security...different funding sources.

PCVS, all adult family members should contribute to a household, don't you think? It helps a person feel some self_worth to pay their own way.

You cannot declare any expenses related to someone UNLESS they are your dependent.
If you declare him as a dependent, it could affect his SSI and any Medicaid benefits. Consult a tax preparer familiar with your state's rules and see which benefits you and him the most.

While it won’t help for 2017, Donald’s newly passed tax reforms may help you out going forward.

There's a new tax credit for non-child dependents, like elderly parents.
Taxpayers may now claim a $500 temporary credit for non-child dependents. 

This can apply to a number of people adults support, such as children over age 17, elderly parents or adult children with a disability.

TG, why doesnt your dad pay rent?

You say he covers his expenses, but he doesnt. You give him money every month. AND you house and feed him.  Doesn't Dad deserve the dignity of paying his own way?

Think about visiting an eldercare lawyer and setting something up.

Parents are not boarders they are family. On the other hand, if the parent has a lot of money, paying rent might mean the difference between "gift" and "expense" should the need for Medicaid arise. Lawyers and accountants should have those answers.

This might be a good time to set up an agreement with your Dad. Make a contract.
You can charge hourly rate for care giving.
You can charge to take him to the Dr.
You can charge for food that you buy that he consumes.
If he is living with you you can charge him a portion of the gas, electric, cable, phone, water, garbage service, newspaper and anything else that might be a household expense this would include snow removal and lawn service. (Easiest way to do this would be to divide the bills by the number of people in the house. 5 people he would pay 1/5th of each bill) Save all receipts so if there is a question later on you can provide proof that the charges are legitimate.)

By care giving I would also consider doing laundry, cleaning, and any help that might be needed. Even if it was totaled out at 7 to 10 hours a week. Laundry, cleaning, making dinner is easily an hour a day. At $14.00 an hour for that type of work. It would add up pretty fast. Let's split the 7-10 hours and call it 8 1/2 hours a week. Roughly $161.00 a week, $644.00 per month and that is just the daily items. The bills and transportation added to that.

***To tgengine...If your Dad is a Veteran he may qualify for Adult Day Care as well as getting needed supplies through the VA. Things like Pull ups. gloves, wipes may be obtained through the VA. This can be a great savings to him and or you.

PCVS has an excellent point, but if the parent has a lot of money, the need for Medicaid probably won't be an issue.