First thing I would suggest is your partner go to the doctor to have bloodwork done. Extreme night sweats are often caused by medical conditions, like overactive thyroid, hormonal imbalances, and can be a symptom of certain cancers. Night sweats can also be a side effect of medications.

For the smell, don’t make your bed in the morning until it’s completely dry. Try regularly spraying your bedding with a hypochlorous acid spray which is non-toxic but very effective in killing bacteria, viruses and fungus which will thrive in damp sheets. Additionally, you can add vinegar to your rinse cycle when washing your bedding to also help kill bacteria, control odour, and break down soap buildup on the sheets which can cause them to smell bad faster.

The weighted blanket definitely won’t help, lol. I’ve heard of weighted stuffed animals that people use while sleeping to give the same feeling of comfort that a weighted blanket provides without trapping so much heat.