Dull Men's Club

I love Pothos, they're very forgiving and they communicate very well. They're very good for people who tend to kill plants by loving them too much — I tend to water mine when they're visibly beginning to look a bit sad. I don't do stuff like spraying (I've found that this can lead to rot, and that I have an easier time keeping plants happy by thoroughly watering them even when the soil is dry at least an inch deep)

What I really love about them though is how easy they are to propagate through cuttings. Great for sharing with friends, plus it's a great way to make an existing plant more bushy — just take a cutting that has at least one leaf node on it (I usually go for at least 2) and then stick it in the existing pot. I was especially grateful for this after I had to live in a fairly low light room and my Pothos had become a bit leggy due to stretching out to try to reach more light.

It sounds like looking after this plant might only be a temporary arrangement, so pruning is likely beyond your job description. If that's the case, you should ask your mom if you can take a cutting or two when it's time to give it back — I bet your daughter would enjoy that.

Edit: I felt like I explained the cuttings thing poorly, so I took another look at the pic to see if I could give an example, and I saw a stem with no leaves on it, and that's a great example of where I'd prune. Here's a pic that shows where I'd make a couple of cuts, and then I'd stick those stems into the soil, an inch or so deep.

Unfortunately, while I was there, I noticed a few signs that might be indicative of overwatering/potential rot. The surface of the soil near the bottom of the pic looks like it's got some fungus growing on it. That in and of itself isn't a problem, but it is a sign that the soil could probably do with having more chance to dry out between waterings.

Furthermore, some of the stems look like they're beginning to get a bit wrinkly, and that tends to be a sign of root rot. If you give the stems a gentle squeeze with your fingers and they feel soft, then that's likely the case. There's no need to worry if this is the case though — this guy still looks pretty happy, so this is likely fixable by watering less often. When I first started out with houseplants, I watered them a little bit, quite often, but I didn't learn until after I'd lost a few plants that thoroughly watering, less often is best.

By thorough, I mean watering over a sink or similar until water is freely running out the bottom of the pot. "Bottom up watering" can also work: this is when you place the plant in a container of water (about an inch deep) for half an hour or so. It'll suck up the water it needs, and you'll be able to feel how much heavier the pot is (this is especially good if you've gone for too long without watering, because the soil can become weirdly hydrophobic)

I'm sorry to come into this post of pride and be a buzzkill like this. My intention isn't to be an "um actually" kind of asshole, I just think it would be tragic if the plant ended up dying, despite you and your daughter's efforts to keep it happy. You definitely shouldn't feel bad about this happening, because it's pretty common, even for people who are experienced with plants. It's especially likely to happen during winter, when plants are respiring less, and houses are more humid.

My biggest piece of advice would be to use the finger method I mentioned above — poke your finger in the soil, at least an inch deep, and only water if the soil feels fully dry, and teach your daughter that too. I find that this is the most reliable way to avoid overwatering because it's like talking directly to the plant to know what it needs — with this method, you'll find that you'll naturally end up watering more frequently in the more Summery months.

Pothos are pretty drought resistant, compared to many (non succulent) houseplants though, so for these, it's usually better to err on the side of too little water than too much. Here's a before and after watering image of my pothos. Despite looking super sad in the first photo, it perked right up less than 24 hours later. In this case, I'd left it for longer than ideal before watering because I was making a point to an anxious friend, but I usually wait until they look at least a little sad.

If I were in your daughter's position, I might be dismayed to learn that I had been inadvertently doing the wrong thing, so this might be a good opportunity to get her a plant that does enjoy a bit more regular love. Off the top of my head, that could include plants like fittonias (nerve plants — they come in loads of colours and are very pretty), birds nest ferns and calatheas.

Sorry again for being a buzzkill, and I hope this is helpful and not too overwhelming. I genuinely don't believe that you've been doing anything wrong here, even if you change your practice as a result of this post — two months is long enough that it would have died by now if you were genuinely doing stuff wrong. It's likely more due to things like the weather outside, or what your house heating is set to — Winter is a hard time to be a houseplant.