How much are you supposed to heal?

I’m a gold lucio and I play often with my friend who is a gold tank (usually junker queen and Winston). A lot of games that we lose I’ll end with like 18 kills and 7-8k healing. A lot of times he blames me for these games. One particular game we lost I ended with 8k healing 19 kills 9 deaths and he blamed me because our moira had 9k healing and the enemy Moira had 12k healing. He blamed me because I “wasn’t healing enough”. I tried explaining that Moira is the highest heals character in the game and Lucio is one of the lowest but he just told me it’s my fault. Was I throwing? If so how much healing should I aim for? If not what should I do to not lose that game?