Foggy doesn't take it well when he finds out about Matt's nighttime activities. When Matt refuses to stop being Daredevil, Foggy decides to take matters into his own hands. Author's choice whether or not he reveals Matt's identity, but somehow Foggy succeeds in getting Matt committed to a psychiatric hospital (possibly for criminally insane, if Matt's identity has been revealed). Foggy is still Matt's emergency contact, so he comes in to check on Matt and sees him deteriorating rapidly. The sounds of the other patients, the drugs they have him on, etc. all start to cause Matt to get worse mentally/emotionally, possibly even consider suicide.
+if hospital staff are Hydra and experimenting on Matt, or hired by Fisk to terrorize Matt
++Matt thinks Foggy had him committed out of spite/vengence, doesn't get why Foggy keeps visiting
+++all the feels, esp. guilt, from Matt and Foggy
++++Matt really starts to lose it, maybe being gaslighted by staff, maybe starts hallucinating, maybe becomes catatonic
+1000 if Foggy eventually tries to get Matt released