No, Belgium charges inheritance tax on the estate of someone who lived in Belgium.

Belgian inheritance tax is only due if your mother lives in Belgium. If she lives outside Belgium, no Belgian inheritance tax is due unless your mother owned real property in Belgium. Inheritance tax will normally be due in her country of domicile.

Most countries apply similar rules and they tax the estate of their residents.

Some countries such as Spain charge inheritance tax on what a resident beneficiary inherits even if the deceased was not living in Spain.

And some countries no longer have inheritance tax (Austria, Cyprus, Estonia, Italy, Latvia, Malta, Portugal, the Slovak Republic, or Sweden).

The United States are special in that they tax the estate of American citizens even if they were resident or domiciled in another country.