Hallo Anne Kestenbaum
The cemetery is described in Dutch at  https://www.joodsamsterdam.nl/begraafplaats-diemen/ The owner is the Nederlandse Israelitische Hoofdsynagoge which can be found at https://www.nik.nl/nihs-amsterdam/ with an email address info@...
While all this is in Dutch, I am sure that you have a translation program that will give you the key points. And if you write to that email address, I am sure you will get a reply in English.
From the inscription, it looks as if the stone was arranged by his wife.
Hope this helps you.
Regards, Nick Lambrechtsen