While I am very pleased you are perhaps trying to practice positive interactions with your brother and sister-in-law in a safe environment, I'm afraid that using props is not really sufficient to get the most out of the attempt. This is why we have therapists, Twilight. If nothing else it can help discuss appropriate topics of conversation with ponies with whom you have rendered yourself somewhat estranged. I will assume this is what you are trying to do rather than attempting to replace your actual family with 'safe' alternatives.