What's wrong with him?!

My live in bf of 2 years just seems to be getting worse... He constantly over thinks everything, when I say everything, I'm talking days of thinking how he's going to hang a new door up, how he's going to schedule the day to fit everything in, what he needs to get at the grocery store, and for hours he'll just THINK about it. Thinks and worrys about the simplest things. For instance, he tried changing a screen on our window. Catastrophe! Oh no, the frame broke! "Do we have glue?" Later that night..."we're gonna need a new frame", "do you think we have the money for a new frame?" "I wonder where we can find one" (searches internet for hours for a frame) next day "glue didn't hold, damnit!" "We need to get a frame!" .... As soon as he walked away, I grabbed extra strength tape, told him to come help me with something... I fixed that darn frame without a problem with tape thinking about how to for less than 30 seconds !  He does this with everything! He thinks so much sometimes he gets upset. I know he needs help, his doctors gives him medication but never takes it! It's been precribed for 4 years and hasn't taken it once! I begged him to try it, just 3 months, to see if it's help him, he fell back on his word... Punk! How the heck to I get him help if he doesn't want to help himself? He and I know his mother needs help, she abuses her medication, he always says "She won't get help because she doesn't want it". So on top of worrying about everything he worrys about his mothers worries too!