It wouldn't have old knob and tube so all you need to check for is whether it is aluminum wiring which was more common in the mid 1970's.

But he said he has clients that puts them in S Corporations.

Aloha,Simple answer: it depends.It depend on zoning, it depend on NCU (you can find out if your unit currently has valid certificate), it depend on condo’s by-laws and house rules (it will continue to change).Honolulu City and Council is currently tabled several bills to regulate and taxed, we won’t know which bill passes, or continue to amend and when the bill into effect.https://www.google.co.jp/amp/s/amp.thestate.com/news/business/national-business/article229502899.html

As @Tom S. said, but lets figure out your current financing capabilities?

Contact the agent(s) and request rent rolls and expenses to help with your due diligence. 

@Austin S.

Having investor friendly lenders is key as they won't require seasoning and will loan without W2's or tax returns.

However, your income will be based on your 1040's and whatever schedules apply to your situation.

The lady (Betty) who owned the house, husband’ (Jack) died in the 60’s, Betty filed a letter stating that the title was to be transferred to her name but apparently only 50% of it transferred.

Plus my father who is 51 would have the added benefit of having these two properties paid off by the time he's in his mid 60's, probably about the time he will be retiring.My Father is basically my "Private Investor" so to speak because he has cash and I have more time and energy to put into the ins and outs of finding deals and dealing with tenants.