How can someone put money into someone else's business and reclaim it in paid taxes?

Question

I have a family member who pays between $10,000 and $15,000 in federal income taxes each year and I was wondering how he/she could funnel money into my start-up business and get it back after filing taxes. Assuming they became a "member" of my business, which is registered as a domestic LLC under in the state of Georgia, please answer the above and the following.

What tax form must they file?
What purchases are 100% eligible and tax deductible?
Any other tax tricks?

Thanks!

NOTE:
The individual would not be investing liquid assets into the business. He/she would, however, spend his/her own money on capital resources (equipment, consumables, etc) and that's what I'm looking for him/her to get back and qualify as deductible.

Answer 1

If the family member pays that much in taxes then their income is much higher than that.

They can funnel money into your startup business but there probably is little tax benefit for doing that.

They would file they same return they did before.

Answer 2

There are no deductions for investing in a business.

If the business has losses, those losses may be deductable.