ELI5: Can African Dwarf Frogs get depressed?

I don't know if this is the right place to go but I got no help from google.

I was given a pair of african dwarf frogs about 4 years ago and unfortunately had to bury one the other day. The remaining froggy however has changed in behaviour... the first day alone he spent hiding in his little cave (which could be considered normal) but today he has been slowly just crawling along the bottom of the tank, not swimming around like he used to. He still goes up for air occasionally but never swims around or freezes in funny little positions like I'm used to seeing him do.

The frogs were very different in body size so I always knew who was who but neither of them have ever acted in this way.

Just hoping someone who might now about this will find this post.

Is it possible my little froggy is depressed or grieving over the other?