Is there a common phrase people use when learning about the death of a friends family member such as "sorry to hear about your mom" or even "sorry you lost your dog"?

For speaking, we only say เสียใจด้วยนะครับ/ค่ะ (sia-jai- duay- na krub/ka) - it's mean you feel sad about his/her lost.

For writing, ขอแสดงความเสียใจด้วยนะครับ (kor-sadang-kwam-sia-jai-duay-na-krab/ka)............. - to show you feel sad/sorry

For informal, you can say เสียใจด้วยนะ (sia-jai-duay-na) - sorry to hear bout that

For speaking, we only say เสียใจด้วยนะครับ/ค่ะ (sia-jai- duay- na krub/ka) - it's mean you feel sad about his/her lost.

For writing, ขอแสดงความเสียใจด้วยนะครับ (kor-sadang-kwam-sia-jai-duay-na-krab/ka)............. - to show you feel sad/sorry

For informal, you can say เสียใจด้วยนะ (sia-jai-duay-na) - sorry to hear bout that

Thanks, it has come up a few times and all I could really do is nod with a sad look on my face. I have an old friend who I expect one day soon his family will tell me has died. I want to be able to express myself better for him.