Can I pick a brain or two?

Thinking about buying a 2015 Impreza 2.0i wagon. Seller says it only has reverse, 1st, 2nd and 5th gear. States he’s been driving it like that for years and expects another 3 to 5 years of life as is. Wondering how true that could be and or if it would be something worth fixing if I bought it. Any and all advice is super appreciated🙏

Update

You people are awesome. Thanks a whole bunch for all the thoughts and helping me realize it’s more than likely gonna be more trouble than it’s worth. It really is appreciated to the greatest level🙏