Belinda, I would first and foremost get the returns all prepared so you can see what the damage is from a liability perspective. It seems the IRS is currently in first position with a 2014 tax assessment of $70,000, but was that from an Substitute for Return or did the client file it?
Prepare all the returns, including the ones for any year with an SFR. If the client can indeed full pay everything then I would file them each with payment attached. Any interest and penalties that show up should just be paid as well, and he is done.
If he in the end cannot pay then this gets interesting, as there might be a strategy to:
1. Pay the IRS 2014 liability
2. File all the CT returns and set up an IA with them
3. File the IRS returns and get the IRS behind CA so the IRS will allow a full CA payment as an expense
Keep me posted as you progress through this, but the critical thing now is the 13-18 return prep.
Good luck, and make sure you take a good retainer for this!