No advice that has not been given .... other than making sure everyone is consistently on board with supporting proper sleep ... all it takes if for one adult in the mix to be going against the grain and it will take that much longer for the child to learn to self soothe through natural wake cycles to stop 'waking entirely up' during them.

I had a child start at 8 months who the entire mat leave mom claimed he never napped more than 20 minutes at a time for her during day and 2-3 hours at night with an hour of screaming in between ... but IMO that is because the kid 'talked in his sleep' which mom was interpreting as being ready to get up so she would here him start go in and get him up ~ and couple hours later he would have another 20 minute nap.

Here I saw the eyes were closed and he was still laying down and not 'in distress' so initially first couple days I just 'rubbed his back' and shhed and he went back to sleep and than over time just waited / ignored it and after a few minutes it would stop and he would settle back into deeper sleep ... the child since his first day here had 60 minute morning nap with crying out at 20 minute mark and than after hour he would 'sit up' without the cry indicating he was done and a 3 HOUR afternoon nap with same 20 minute cry out at start and than again about 1.5 hours in but again eyes closed and still laying down so just waited it out. Now after 10 months here he only cries out / talks in sleep when he is fighting a cold or teething otherwise he sleeps soundly the solid 3 hours in afternoon ~ we are weaned off the am nap now.