Own half a duplex, other half going up for sale privately

[Gage R.]

Hello, just wanted to reach out and get some advice. I just purchased a half a duplex about a 3 months ago. After living here for awhile we noticed the other half was vacant. We talked to the owners family member and said they would be willing to sell it soon because of her mother being in a nursing home. What is the best way to go about purchasing the other half. Can I purchase with another loan or add it to my current mortgage and create a single mortgage? Could probably rent the side for $1100 and looking to purchase for 60-70k. Any advice would be helpful. Thanks!