Whatever you decide... do NOT wean or change the routine of a baby/child... when they are going through a growth-spurt. WRONG timing. It will not bode well.
AT about 18 months old... this is a growth-spurt time and a MAJOR time of developmental changes and hitting milestones and/or teething. Which tweaks their sleep as well. Because, ALL of these things may be happening at the SAME time. That is a LOT of things for a baby to deal with.
Also, some babies cannot nap, because they are either OVER-tired and past the "window" of when they should have napped... and then because they are OVER-tired, over-tiredness makes a baby UN-able to sleep nor to sleep solidly, and it causes them to wake more. OR, the baby is over-stimulated to close to nap/bed time. Use a consistent routine, everyday, PRE-nap.
And, maybe... he is just hungry.
It's all about timing....and going by your baby's cues.
All the best,
Susan