Pressure wound getting bigger

Hi there, I am a caregiver for my brother. Back in 2014 he had osteomyelitis due to a pressure wound on his bum, we learned a lot through this. But that wound never fully healed. So over the years we have been using hydra ferra blue for packing the wound and going Back-and-forth with different dressings. Basically just maintaining the wound. Recently he had to get up a lot just the way things work out sometimes, but it aggravated the wound and now it has gotten much bigger and has a lot of drainage now. He went to the Wound clinic, The doctor was not there so he didn’t get to really have much done. He goes back again this week. In the meantime we’re not really sure what to do. Would love any advice. He’s already been in bed for so long. He does get up 3 Times a week to do a bowel program and shower So that’s about three hours in the shower chair with a Rojo cushion. And on Sundays he gets up and his power chair with a Rojo cushion for maybe 6 to 7 hours. The rest of the time he’s in bed on his side for the most part. He sits up to eat and then gets back on her side. This has led to a lot of shoulder pain. He does have an alternating air mattress. Any advice would be considered helpful. Thank you so much and advance!