His eye looks closed up, so I would clean it with some saline and a warm compress, the put in some Neosporin or Terramycin ointment. A vet may have something better if available. I haven't treated pox this bad, but most say that if you can keep them eating and drinking, and prevent secondary infections, they will do okay. Iodine on the scabs away from his beak and eyes may help dry them up. Look inside his beak if you can for any yellow patches that could be wet pox, and can block his airway.
Thanks! I've just been sitting on my hands because I keep reading that there's nothing to do about it. I hate seeing them unwell.
Use the saline to flush it, or as part of the compress? And does compress just mean like to hold a warm washcloth over it? Is there any way to clean up foamy eyes in the future? I'm assuming that's why it's closed over.