I would try to follow the routine From home. My 4 yr old rarely sleeps at all now.

As a Nana myself, I think you will have to follow what your daughter in law wants in regards to the number of naps. My two year old grandchild only has one nap. If he had two naps he would end up going to bed late at night. Can u put your grandchild down at the same time that your daughter in law does? Many five year olds don’t have a day time nap anymore, they just have an hour’s quiet time. All the best.

I think you should try and stick to their normal routine.

1 sleep per day at that age is normal, 5 year olds generally don’t nap but every child is different and have different sleeping needs.
You’re best off looking for the tired signs in miss 2, being the rubbing of the eyes, yawning etc

Children can also have quiet time to just sit and read/look at a book and relax and maybe fall asleep too.

Children sleep when they need it and growing bodies need plenty of sleep time.

Yes I’m like you I feel if a child is tired let them sleep. Adults do. Xx

At 1 year and 7 months my daughter stopped sleeping during the day. She just slept 12 hours in a row at night, but no naps at all during the day. I found it weird at the beginning and for some days I tried to let her have a nap. But she didn’t like it and she didn’t need it. She was happy during the day and slept happily during the night.
If a child feels tired, in my idea he should go to sleep.