Difficulty understanding loans

[Jonathan B.]

Would very much appreciate if you could have some time in helping me understand how credit and mortgage loans work?

I'm looking into investing with my father, he has the equity and would like to understand the general idea of how do I increase my ability to leverage my cash while I increase my portfolio​?

Given he has 500K in cash,

He is retired, and has no other income

How would one's situation be able to roll forward given such condition?