Is this man using my mother?

My mother is a widow and recently began dating a man her age. I was happy about this at the start because she has been depressed and lonely for many years, but I have also begun to feel uncomfortable about the man she is dating. I can’t tell if he genuinely loves her and wants to be with her or is just looking for a companion and someone who still has money in her bank account. I don’t know how much information about her finances she has shared with him, but it worries me because I know my dad left her a large amount before he passed away. What can I do to make sure this is someone who will not make her life harder than before?
You can voice your fears, give her your reasons for why you feel the way you do, and consider steps that allow you both to protect your financial conditions to put your mind at ease. She may prefer that too, because it is always wise to separate finance from emotion. If your comments upset her, you can continue doing what you already are, which is making sure you have an eye on her and this person, and telling her you are always around if she needs someone to talk to. Trusting her partner will take you time, but you can gauge him and his intentions better only when you spend more time with him. To assume the worst without knowing him well enough may be unfair.

I have been married for three years, and the only cause of friction between my husband and I is his relationship with a friend whom I cannot stand. I think he’s a bad influence but my husband has been friends with him since their school days and I can’t do anything about it. How do I cope with this?
You have presumably made your feelings towards his friend clear. If nothing can be done, why not find ways of avoiding him to keep the peace?