Help (again lol)
I cant remember a certain bl manga I've read

The stories is about a guy (uke whose parents died already) and the seme who took him in(rich bar owner/underground.. They became lovers later..)
And now there's this chapter in which the uke's grandfather(apparently he's rich cause his momis rich) wants the uke to take over the company(cause the grandfather is sick with cancer I think).. and then there's also the adopted younger brother of the uke..

I guess it's Love Mode - pairing Aoe Reji X Naoya. What you described about the grandfather happens in vol. 5.