Stressedtothemax - Welcome! I'm sorry I had to meet you here, but this is one of the greatest places this side of heaven. You will get great help and advice here. I've been at this coming up on 13 years from onset of symptoms with my husband, Brian. Then he was trached/vented 7 years ago. He too is bed bound and before his computer that allowed him to speak, we too used a letter board. When he's not in front of his computer, like when ready for bed or first thing in the morning, I will ask him general questions and then get more defined, like is it with your body? If he indicates yes, by blinking for him, then I will do a scan of his body, head to toe until he blinks that is the problem, then I will ask more yes/no questions as to the problem with that. If its not his body, I will ask about his bed, then the room etc. Broad then narrow. Again a letter board, or a board that has pictures of things he might need/want makes it easier until you can get a computer. Also, Brian uses the little movement he has in one thumb to operate a switch to use his computer. They can almost use any muscle that will work to work a switch, so if he can't get the eye gaze, get a good therapist out to assess any little twitch he can make.
I'm happy to hear you have a small amount of help. That makes a huge difference. If you can go to therapy, trust me - go. I finally started this summer and I have found it very useful. It's individual, for me more comfortable. However, this forum started it all and probably still would not be going if it wasn't for this place getting me on the right track.
To have fun and find joy here is what I do. I'll tease Brian about something and it makes us both happy. Like he has a lot of mucous - not fun, but I'll call him bubble man in a loving way. Or if there is something that you know your son loves and brings him joy, do what you can to help him to see that, maybe a youtube video. If you have a tablet or even you phone, you could hold it in front of him. Or a blue ray player or smart TV. When you see that he is happy or finding joy, you will too. If you do something and it turns out wrong, make fun of yourself. Turn that incident into something silly or an inside joke. If you wait for the joy or fun to smack you in the face you won't find it. You have to make it, just as in life w/o ALS.
Also, it may be possible that you are depressed as well. I know I was on some Celexa for a few years, others here have been on Zoloft. There is no shame in needing that help to get over the hump. What we deal with is hard. I could not imagine one of my kids going through this, it's tough enough with my husband. So do take time out to talk to your PCP at least.
You mentioned faith - pray, find some good devotionals. Remember God is out there for you, but you have to ask for help.
We are all here for you.
Hugs,
Sue