I dunno how relevant this PAN doc was, but it did say it had two kinds of Tunnel Monitoring: one was DPD and one was a ping of sorts and either of them would bring down the tunnel. https://knowledgebase.paloaltonetworks.com/KCSArticleDetail?id=kA10g000000ClFaCAK#:~:text=DPD%20is%2...
Again, I have zero background on this and I'm just parsing "vendor words" to mean something. This might not even be useful, but in the off chance it is... then ok.
For DPD on the Check Point side, you'll need Permanent Tunnels enabled to do the same. The Site-to-Site VPN admin guide has a whole section on DPD that might be worth a read, plus a ckp_regedit command that could be useful.
Good luck!