My grandfather wants to put me on his shares in a co-op.Need help

[Chris Breezy]

He wants to put me on his shares or shall I say stock in the co-op so it would be basically 50/50 in the unit.  my question is just how would this affect me at all because I currently own no real estate but I plan on buying a dueplex soon . 

Would this effect me on any first home owner loans since I own stock in the co op?

The Mortgage is paid but their is still a monthly hoa of 500$ , how would this effect my taxes ?

Would he be allowed to put me as owner of the stocks even if my credits bad?