Looking for advice on best use of space for commercial lot in Delco.

[Ryan Steiner]

A close friend of mine has .8 acres in Delco with a 5 br sfr on it in the front of the lot. He is wanting to build 2 additional 2 br modulars on it. I said I thought I heard they were even doing 4 unit apartment buildings now? I'm just a novice flipper, I don't know much about zoning, other than it is zoned commercial. 

He was originally looking to sell it as a commercial lot but has been unable to sell it so wants to atleast collect a little more rent. Looking for any advice on how to proceed or where to even start? Local zoning&permit office? Thanks in advance for any help!