that sounds right..but all that effort to deal with a psycho and cover up killings for I guess half or less of the money and surely he gets a fairly good wage being a dr?

My impression was that Montclaire was worth a lot of money, and they likely were promised a cut of the profits of its sale or partial ownership.
"I'd say this cloud is Cumulo Nimbus."
"Didn't he discover America?"
"Penfold, shush."

I am still confused what Connie and the Dr got out of it? Can someone explain?

Rita came back to the house disguised as "Mrs. Ryan", the new patient in Linda's nursing home. Her 'nephew' (a fellow psychotic patient no doubt) was her helper, it seemed. I truly believe Connie & Dr. Barton were in cahoots with Rita to drive the mother crazy, and were either not expecting Linda to want Montclare or they didn't know Linda was the beneficiary. Rita wanted Montclare, for money and for revenge (and probably her own psychotic reasons too like killing more people). She most likely promised Dr. Barton, Connie, and her 'nephew' shares in the money and of Montclare. Dr. Barton released her, and he Connie and the crazy duo tried to drive Linda crazy like they did her mother.
But they didn't take into account (oddly) that psychos like Rita and her 'nephew' would kill
them
too.
"I'd say this cloud is Cumulo Nimbus."
"Didn't he discover America?"
"Penfold, shush."