Mono and onset depression

My 13-year old grandson was diagnosed with mono 2 weeks ago.  He has missed school for the last 4 weeks due to severe breathing problems, lost his voice, etc.  He is now having bouts of extreme sudden depression - stops talking, his lips quiver, and he seems to want to cry.  We could be playing cards, or even ball outside and he's very normal.  Then all of a sudden he stops talking and becomes extremely sad,  He can barely talk when this happens. These bouts may last anywhere from 5 to 10 minutes, then he appears to be until the next time. This occurs several times during the day.  When I mention to him that he needs to try to ready himself to return to school, or practice piano for his weekly lessons (hasn't attended in a month), that seems to bring on stress and the sadness.  Has anyone you know experienced this? Is this because of the mono, and if so, why - he is no longer on any type of medication.  I am so worried and I don't know how to help.  Any words of advice or wisdom is appreciated.  Thank you.  

[darlenedaisy]

I would suggest you keep a daily journal of his moods and behaviour, and take it to the doc.  

[BG18]

Thank you - this is a good idea.  Bless you.  

[Vintage_Rabbit]

i had mono when i was 16 but i don't remember having those depressive bouts.  I hope he is ok