Need feedback/input on an investment 4 unit plex college property

[Sage White]

All,

Need your opinion on this before I decide to walk away from the offer.  I have a seller who called on a yellow letter campaign.  He is out of state and wants to sell his interest (50%) on a property that is income producing and a couple of blocks from a college campus in Arizona.  His name would be replaced by my name on title.  He has been a silent partner and his other partner has managed everything to keep the property occupied.  What I have been told is the property is always rented and this property is in a historic district.  He is open to seller financing his interest with a little down and willing to go 7 years with the financing.

My questions to those who buy multi unit rental properties are the following:

1)What have your experience been for those who ever bought property like this?  Or pros/cons for anyone who wants to comment

2)What numbers should I be looking for once I get a copy of the last 2 years of documents that show proof of rents.

Thanks,

Sage