Glaucoma can be a concerning issue. Since he has multiple comorbidities, I would recommend eye drop Dorzox - one drop in both eyes, 3 times a day and Eye drop cmc - 1 drop in both eyes, 3 times a day. With a gap of atleast 5 minutes between both the drops. This is only for the time being so that his pressure will be under relatively control. He will require a detailed evaluation as soon as the lockdown is over.

The medicine depends on type of glaucoma,extent of loss,level of iop with present treatment if any. So Better will be to initiate an online consultation with anybody Or consult an ophthalmologist nearby.

Is he already on some medications for glaucoma ? There are several different medications for glaucoma. Firstly, we need to know what type of glaucoma. Then what are the eye pressures, the optic disc findings, OCT, RNFL, HFA. Also his other comorbidities like heart disease, asthma, diabetes, etc.

To measure IOP and being diabetic ,better to consult nearby ophthalmologist.

Need to have detailed evaluation. Cannot prescribe drops until he's been checked and evaluated.

Is he already on medications? What’s his eye pressure?