I am very sorry to hear, that you already have a progression after such a short time.
I guess you already had Temozolomide as chemo.
Did you doctors suggest a change of the chemo agent like procarbazine, CCNU or maybe an angiogenesis inhibitor like Bevacizumab?
Were they able to do a biopsy of the tumor to determine the MGMT-status or is it too risky due to the location?
Where are you from?
Maybe there are viable clinical trials that are still recruiting in your country.
Your doctors might be able to get you the contact informations for such trials.
I suppose most of the users here on the forum aren´t well versed in english.
For english speaking support groups it might be worth checking out reddit(dot)com, specifically the subreddit r/braincancer.
There are also a few english speaking forums like the "cancer survivors network"
or the "macmillan cancer support" group and a few more.
You can find them via google by searching for "brain cancer forum" or the names of the groups.
The brain cancer subreddit on reddit(dot)com seems to have the most participants.
There is a facebook group as well, called "DIPG Support & Awareness", which might be the most suitable for your specific diagnosis.
Of course you are always welcome to ask questions here, if you feel like it. The few english speaking users here will certainly try their best to answer you as good as they can.
I wish you and your relatives all the best, and hope that you`ll stay strong despite that grim diagnosis.