Early 40's friend recovering from radical mastectomy. Should she have counselling or clinical psychology session?

Yes. Breast cancer in women under 50 can be difficult to accept and handle. It is important to have a good family or friend support system. It helps to get involved with a local breast cancer support group. Getting professional counseling is a good idea especially if one is having difficulty accepting diagnosis and moving through daily life activities. No one should go through this alone.
It depends on her. If the surgery make her feel down and have low self esteem , which is usually the case , than yes she need to see a mental health professional for medication and therapy.
Discuss with her MD. The answer is yes the question is the timing a radical mastectomy implies a a larger extent of surgery than we normally do ie. The muscle was taken and usually no reconstruction at first. Usually chemo at age 40 and radiation- if muscle involvement - that is big surgery----- I have done 6 in 30 years of pvt. Practice outside the cancer hospital setting. No one should go through that alone.
Maybe. It depends on the person; if, after a radical mastectomy she feels anxious and depressed, perhaps several sessions or so might serve to help her discuss her fears and, perhaps, a sense of loss.
Body image . Such a procedure Often R aises profound questions about how woman feels about her body. Find a reputable psychotherapist who deals with the feminine issues and or body image issues. A woman can discuss how such procedures affect not only her body but her self perception, and her emotions.