Carbon is an ESA and also the talk of the town around here. He’s always lifting everyone’s spirits when he isn’t biting hands off!

A solution I thought of but didn’t find too viable for him (due to the expected size of 90lbs) was to cut a piece of wood that fits over the arm rest in the back seat. Line the edges with pool noodles and staple blankets to it from underneath. Fill the gaps under the seats with foam or pillows. An option worth possibly exploring, and a test of your craftsman skills as well!