Elderly chihuahua found 23rd Ave E

My friends found and caught this tiny brown and white elderly chihuahua last night around 23rd Ave E and John. They took him to the emergency vet and he has no chip and we were told he has a heart murmur. None of the shelters are open today so we are keeping him safe but he needs his medication so hoping to find his owner asap. We don’t want him in a shelter to be put down :/