We have a number of posts about the pronunciation of "h" and this one Do any dialects of Spanish still pronounce "h"? refers to the entry in the DLE for "h"
- f. Octava letra del abecedario español, que en la lengua estándar actual no representa sonido alguno, si bien se aspira en determinadas voces de origen extranjero, como hámster o dírham, y en algunas zonas españolas y americanas como rasgo dialectal.
Although the word alcohol is derived from the Arabic I hardly think it can count as a foreign loan word anymore. If the "h" is not pronounced are both "o" sounds pronounced or just one? Is the same allophone used for both https://en.wikipedia.org/wiki/Spanish_phonology#Allophones ?
My curiosity about this was raised by opening the beer can and seeing that, if we ignore English, two of the four remaining languages drop the "h" (French and Portuguese) while two retain it (Spanish and what I take to be Catalan cervesa sense alcohol)