Thanks to pps for the additional support and input
In addition to pps advice I want to say, from experience and from what Tracy says in her books (although I am not quoting), your LO looks to YOU for the routine and to show him the way. Yes much of EASY is about following cues and reading your baby's needs however I'm sure you'll remember Tracy said babies do not set the rules or the routine. So if we look at feeding as an example, if baby is snacking every hour we observe this and interpret baby's need - to have fuller more satisfying feeds and to stop snacking (many reasons, 2 are that breast fed babies need hind milk, and all babies need to eat enough to see them through A time and S time). So there is example of interpreting baby's needs to encourage healthier eating routines.
With sleep it is the same - Tracy didn't tell us to blindly follow baby's desire to sleep here or there or for this amount of time, but to observe and interpret their need and then shown them the way to healthy restorative sleep which ultimately will make them happier little beings. IMO your baby (as is typical for the 3-2 transition) is giving many signals that he needs to move to 2 naps. He doesn't know how to do this alone so there are phases of him short napping, phases of crashing out in the car for 2 hrs, NWs, EWs... and so long as you allow this to go on he will continue to be somewhat lost in his routine, days will never be predictable for either of you and his cycle of UT/OT will continue.
I know it is terribly hard to decide which way to go, and what to do (been there, and thank goodness for this forum, I've said it before, we all end up here when we are lost and need help working out our baby's needs) but I really think you need to decide on a plan, write it down so you know what your plan is and stick to it.
For instance if you are going to drop nap 1 with preference for naps 2 and 3 to remain (which was mentioned as an unusual but possible plan) you need to take that in hand and make it happen. Not try to resettle after 40 mins but cap at 30, then 20, then 10 then stop offering the nap - and this happens rapidly to get him on a regular, predictable routine.
If on the other hand you now want to work at keeping naps 1 and 2 and drop nap 3 (more regular plan) you need to make that happen. Push the A right up to a suitable time, and teach him to sleep whether or not he cries. I KNOW crying is not nice, but like I said before Tracy was not at all against baby crying during sleep training so long as you are with him, and she was not at all against very long A times (mega long - look back at reply 33 for example and page reference for a much younger baby forced to longer A times than your LO during sleep training), you would need to commit to teaching him that it is nap time whether or not he sleeps or cries you continue to teach him it is nap time.
Which ever you choose you need to know where you are headed, so that baby knows where he is headed and you need to fully commit to the plan.
What comes to mind for me is my DS's 2-1 nap drop, different nap drop but more work and crying than I ever expected. He'd been doing a 2hr nap reliably every day for so long I never thought that could be disrupted - wrong - as his CN was dropping and as I was offering EBT in response his regular 2hr nap disappeared! Varying in length to begin with and leaving him massively OT on 20 or 40 min naps, sometimes 1hr... the solution was for me to tell him it was nap time and stick to it no matter what. I did W2S every 20 mins for the entire nap in attempt to keep him asleep. Often it worked, when it didn't and he woke fully I began resettling in the cot until he screamed, when he screamed I picked him up and held him and continued to tell him to sleep, he screamed and screamed and screamed with me whispering in his ear that I loved him that he was not alone and that it was time to sleep. Eventually he passed out in my arms and I put him down in his cot, continuing with a hand on him until his sobs and judders faded. And 19 mins later I was back in his room to W2S him through the next 20 min mark. And I just kept on going until he had a minimum of 2hrs sleep. Believe me it was not nice, it was damn hard. But it was worth it for him and for me. And eventually he was able to see himself through that nap again and we were through the nap drop and out the other side (and that nap remained from roughly 12 months to over 2.5 years).
Short naps are common between 4 - 6 months but they can happen at any age when LO needs a new routine. It can be smooth sailing with a small tweak in the times or it can be utter hell. Either way, I honestly think the way through is to get it done and the sooner you start the sooner you come out the other side.
hugs
