I’m so sorry for your loss. Sending you hugs
The amount piggies drink varies widely (some drinking hardly anything and others drinking a lot ) but it is important to note that the need to drink comes before the need to eat. Therefore, if he truly isn’t drinking anything then he also won’t be eating enough.
Consequently is he is eating, then he is going to be drinking.
Either way, switch to daily weight checks so you can more closely monitor his hay intake. This means you can step in quickly with syringe feeding if there is to be an issue with hay intake.
Where a piggy is otherwise ok - eating, maintaining weight - then you have time to come to terms with your loss and for your boy to grieve. Generally you have around four weeks to find a new friend.
If a bereaved piggy goes into acute pining (which is rare), stops eating, loses weight, then (assuming illness is ruled out), getting a new friend then becomes urgent and needs to happen asap.
Generally, a baby/younger piggy is best as they will not challenge the hierarchy. However the primary consider in any bond is character compatibility.
The best way to find a friend is with the help of a rescue centre who can help character match with a new friend. That isn’t always an option for everyone (and in the case of acute pining, you probably wouldn’t have time to go through the rescue process anyway) so if you need to buy a piggy and then do the bonding process yourself, it is wise to have a plan b for living arrangements (living in separate but side by side cages) if the bond fails.
I’ve added a guide below to help you further
I hope that helps.
Looking After a Bereaved Guinea Pig